Extended range communications for ultra-wideband network nodes

ABSTRACT

A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division of U.S. patent application Ser. No. 15/803,220,titled “Extended Range Communications for Ultra-Wideband Network Nodes,”filed on Nov. 3, 2017, which claims priority to and the benefit of U.S.Provisional Patent Application No. 62/438,683, titled “UWB ExtendedRange Communications for Patient Care Devices,” and filed on Dec. 23,2016, U.S. Provisional Patent Application No. 62/438,831, titled“Estimation of Interference in Wireless Communications,” and filed onDec. 23, 2016, and U.S. Provisional Patent Application No. 62/438,814,titled “Burst Rate Selection for Ultra-Wideband Communication,” andfiled on Dec. 23, 2016, the disclosures of which are incorporated hereinby reference in their entireties for all purposes.

TECHNICAL FIELD

The subject matter described herein relates to interference estimation,burst data rate control, multipath degradation mitigation, enhanced datamessage structuring and data spreading to wireless communication forrobust data communications supporting various data rate transmissions tonodes within the wireless communications network.

BACKGROUND

In communication networks, wireless signals can be influenced byinterference and multipath which can distort the signals received by areceiver, causing a change in the data, or a failure of the data to beproperly transmitted to the receiver. The receipt of distorted signalsat a first network node from a second network node can require (1) atransmission of a failure message being sent from the first network nodeto the second network node, and (2) retransmission of the data.Retransmitting data can be inefficient and increase the network trafficproducing additional interference within the communications network.

SUMMARY

In one aspect, the presently described subject matter is directed to adata system. The system can include one or more of the followingcomponents. Examples of the components can include a data generatorconfigured to at least generate data. A spreading code generator can beprovided that is configured to at least generate a spreading sequencefor the data. A signal generator can be provided that is configured toat least generate an ultra-wideband modulated signal of the data fortransmission. A direct sequence spread signal generator can be providedthat is configured to at least generate a direct sequence spread signalby combining the spreading sequence to the data. A signal modulator canbe provided that is configured to at least map the spread data to one ormore signal elements of the ultra-wideband signal. A transmitter can beprovided that is configured to at least transmit the direct sequencespread signal elements of the ultra-wideband signal.

In some non-limiting variations, one or more of the following componentscan be included in the system. A data cipher can be provided that isconfigured to at least encrypt the data. A chip cipher can be providedthat is configured to at least encrypt the direct sequence spreadsignal.

In some variations, the spreading sequence can be a time-based spreadingsequence that spreads the data. The time-based spread data sequence cancomprise a sequence of chips and the direct sequence spread signalgenerator can be configured to at least interleave the sequence of chipsthat are mapped into modulation symbols in the ultra-wideband signal.

The spreading code generator can be configured to at least change astart location for the spreading sequence of each symbol in the data.The direct spreading sequence can be spread across some or all thesubcarriers of the ultra-wideband signal. The ultra-wideband signal cancomprise multiple subcarriers and the spreading sequence can be spreadacross some or all the multiple subcarriers. In some variations, thespreading code generator can comprise a time-based spreading codegenerator for generating a time-based spreading sequence. The spreadingcode generator can comprise a frequency-based spreading code generatorfor generating a frequency-based spreading sequence.

In one aspect a method is provided. The method can include one or moreoperations. The one or more operations can include generating datarepresentative of information generated by one or more input devices. Aspreading sequence can be generated. An ultra-wideband signal of thedata can be generated. A direct sequence spread signal can be generatedby combing the spreading sequence to the ultra-wideband carrier signal.The direct sequence spread signal can be transmitted.

In some non-limiting examples, one or more of the following operationscan be added. The data can be encrypted. The direct sequence spreadsignal can be encrypted. The spreading sequence can be a time-basedspreading sequence. The time-based spreading sequence can comprise asequence of chips. The operation can include interleaving the sequenceof chips mapped into modulation symbols in the ultra-wideband signal.

A start location for the spreading sequence for each symbol in the datacan be changed. The spreading sequence can be a frequency-basedspreading sequence. The ultra-wideband signal can comprise multiplesubcarriers and the spreading sequence can be spread across the multiplesub carriers.

In one aspect, a system is provided that is configured for introducingdata redundancy into wireless communications, and in particularultra-wideband (UWB) wireless communications to increase thecommunication range and combatting multipath degradation whentransmitting data that operates at lower transmission rates.

Implementations of the current subject matter can include, but are notlimited to, methods consistent with the descriptions provided herein aswell as articles that comprise a tangibly embodied machine-readablemedium operable to cause one or more machines (e.g., computers, etc.) toresult in operations implementing one or more of the described features.Similarly, computer systems are also described that may include one ormore processors and one or more memories coupled to the one or moreprocessors. A memory, which can include a computer-readable storagemedium, may include, encode, store, or the like one or more programsthat cause one or more processors to perform one or more of theoperations described herein. In addition, computer systems may includeField-Programmable Gate Arrays (FPGAs) or custom Application SpecificIntegrated Circuits (ASICs) that may implement sections or the entiredesign of the current subject matter. Computer implemented methodsconsistent with one or more implementations of the current subjectmatter can be implemented by one or more data processors residing in asingle computing system or multiple computing systems. Such multiplecomputing systems can be connected and can exchange data and/or commandsor other instructions or the like via one or more connections, includingbut not limited to a connection over a network (e.g. the Internet, awireless wide area network, a local area network, a wide area network, awired network, or the like), via a direct connection between one or moreof the multiple computing systems, etc.

The details of one or more variations of the subject matter describedherein are set forth in the accompanying drawings and the descriptionbelow. Other features and advantages of the subject matter describedherein will be apparent from the description and drawings, and from theclaims. While certain features of the currently disclosed subject matterare described for illustrative purposes in relation to a telemedicinesystem, it should be readily understood that such features are notintended to be limiting. The claims that follow this disclosure areintended to define the scope of the protected subject matter.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, show certain aspects of the subject matterdisclosed herein and, together with the description, help explain someof the principles associated with the disclosed implementations. In thedrawings,

FIG. 1 is an illustration of a system having one or more featuresconsistent with the presently described subject matter.

FIG. 2 is an illustration of impact of different multipath signal delayson the reception of an orthogonal frequency division multiplexing signalgenerated by a device having one or more features consistent with thepresently described subject matter.

FIG. 3 shows an example of a typical QPSK direct sequence spreading donein the time domain on a single carrier frequency. Placement of aninphase and quadrature spread data on each of the subcarriers of anorthogonal frequency division multiplexing data spread spectrum signalcan implement this same approach and provides a system having one ormore features consistent with the presently described subject matter.

FIG. 4 gives a top level block diagram of an orthogonal frequencydivision multiplexing data spread spectrum system which places thedirect sequence spreading after the data encryption, data error encodingand interleaving processes and having one or more features consistentwith the presently described subject matter.

FIG. 5 shows a top level block diagram of an orthogonal frequencydivision multiplexing data spread spectrum system which places thedirect sequence spreading after the data encryption and data errorencoding with interleaving being performed on the spread data chips andhaving one or more features consistent with the presently describedsubject matter.

FIG. 6 shows a top level block diagram of an orthogonal frequencydivision multiplexing data spread spectrum system with data being spreadbefore encryption, error encoding, and interleaving, which is done onthe spread data chips, and this system structure having one or morefeatures consistent with the presently described subject matter.

FIG. 7 is a process flow diagram showing a process having one or morefeatures consistent with the presently described subject matter;(comment need work here; what is being presented).

FIG. 8 is a ultra-wideband (UWB) network illustration of a systemconfiguration with two independent UWB links for a user device to twopatient care devices with the network having one or more aspects of thepresently described subject matter.

FIG. 9 shows a graph illustrating the sequence for time frequency code(TFC) 6 used in a system having one or more features consistent with thepresently described subject matter.

FIG. 10 shows a graph illustrating the sliding correlation output versustime samples for the first and second time frequency code (TFC) 6sequence of the graph illustrated in FIG. 9.

FIG. 11 illustrates a graph showing an example of the time spread of thecorrelation peak introduced by transmit and received filtering alongwith timing differences between the transmit and receive signals, usingoperations having one or more features consistent with the presentlydescribed subject matter.

FIG. 12 is a process diagram illustrating a method 1200 that includesone or more features for wideband and narrowband signal, interferenceand noise estimations at a network node consistent with the presentlydescribed subject matter.

FIG. 13 is the wideband and narrowband signal, interference and noiseestimations process continued from FIG. 12 that includes one or morefeatures consistent with the presently described subject matter.

FIG. 14 is a process diagram illustrating the wideband and narrowbandsignal, interference and noise estimations collection process over theavailable ultra-wideband (UWB) channels at network node that is a methodthat includes one or more features consistent with the presentlydescribed subject matter.

FIG. 15 shows a process flow of a method for estimation of interferenceand having one or more features consistent with the presently describedsubject matter.

FIG. 16 shows a process flow of a method for operating on the presentcommunications channel or selecting a new communications channel andhaving one or more features consistent with the presently describedsubject matter.

FIG. 17 is a process flow diagram illustrating data burst data ratecontrol for robust communications for higher data throughput trafficsuch as video communications that includes one or more featuresconsistent with implementations of the current subject matter.

FIG. 18 is an illustration of a modification to the super frame forincreased data capacity that includes one or more features consistentwith the presently described subject matter.

FIG. 19 is a process flow showing a method for selection of the burstdata rate based on channel estimation and having one or more featuresconsistent with the presently described subject matter.

FIG. 20 is an illustration of a system supporting a low and high datathroughput ultra-wideband communications and having one or more featuresconsistent with the presently described subject matter.

FIG. 21 is an illustration of a system supporting either a low, high orswitching between the low and high data throughput ultra-widebandcommunications to an Access Point and having one or more featuresconsistent with the presently described subject matter.

FIG. 22 is a process flow showing a method having one or more featuresconsistent with the presently described subject matter for addressingthe two UWB data rate configuration, establishing synchronization andpassing channel and low/high data rate operation information in a lowand/or high data rate UWB links.

DETAILED DESCRIPTION

Retransmitting data can be inefficient and increase the network trafficproducing additional interference within the communications network.Efficient sensing and characterization of the communications channelsbetween the different network nodes along with the data throughputrequirement provide the key parameters for proper selection of databurst rate and whether to spread the data for robust communications.Continuous channel monitoring enables transmission parameters to bemodified to support the changing channel conditions versus interference,multipath, communications range, and network topology. Known datathroughput requirements for different network node connections can beused to minimize the selection range of the transmission parametersand/or the assignment of different communications channel for supportinghigher and lower data throughput requirements. Lower data throughputrequirements enable more redundancy though data spreading to be added tothe ultra-wideband (UWB) wireless communications signal for extendedcommunications, multipath mitigation, and/or increased communicationslink margin. Higher data throughput requirement for transmissions likevideo require high burst data rate that can be achieved by selection ofthe an independent UWB channel with the estimated lowest interferencefrom measured channel data that is independent from the lower burst datarate UWB channel.

The range of ultra-wideband (UWB) signals can be increased by increasingthe transmission power of the ultra-wideband signal. Alternatively, therange of ultra-wideband signals can be extended by adding dataredundancy to the ultra-wideband signals. Adding data redundancyrequires transmitting the same data packet multiple times. If a datapacket becomes corrupted during transmission, a duplicate data packetwill be shortly received that can be appropriately combined with thecorrupted data packet for proper reception of the transmitted data.Transmitting the same data packet multiple times can make theultra-wideband signal more susceptible to being intercepted and possiblybe exploited by a third-party. Similarly, increasing the transmissionpower of a signal, to increase the likelihood that the signal reachesits destination, can also increase the likelihood that the signal willbe intercepted by a third-party.

In some examples, multipath degradation, introduced by the extendedcommunications range, can be mitigated by frequency hopping between theorthogonal frequency-divisional multiplexed (OFDM) symbols. Frequencyhopping places adjacent symbols in different frequency channels forfiltering. For example, multiband orthogonal frequency-divisionalmultiplexing (MB-OFDM) can provide a limited maximum data redundancy of4, which corresponds to 2 of the same symbol in both the time (on adifferent symbol) and frequency (on different sub-carrier on the samesymbol) domain. By placing the same symbol on different sub-carriersmitigates performance degradations introduced by frequency nulls in thechannel introduced by multipath destructive interference. This approachcan be expanded by increasing the redundancy in both the time andfrequency domain resulting in extended range at the expense of reducingthe data throughput capability.

Presently described is an approach to increase the data redundancy of atransmission of an ultra-wideband waveform, while avoiding thetransmission of the same redundant data multiple times. This approachcan increase data redundancy while not increasing the likelihood thatthe signal will be intercepted by a third-party.

In some variations, the presently described subject matter can include adirect sequence spreading technique to be applied to the signal prior tothe signal being modulated across multiple sub-carrier frequencies. Forexample, the signal can be the subject of a direct spreading techniqueprior to being subject to an orthogonal frequency division multiplexing(OFDM) process.

An alternative or complementary approach to increase the data redundancyof a transmission of an ultra-wideband waveform, while avoidingtransmission of the same redundant data multiple times, can includesubjecting the signal to an OFDM data spreading technique that isimplemented prior to encrypting the data. Some typical direct-sequencespreading techniques increase the signal bandwidth by multiplying a datamodulation of the signal by a higher chip-rate. However this willincrease the signal bandwidth. The presently described OFDM dataspreading technique can require spreading the data and then mapping thespread data into the OFDM signal. The presently described OFDM dataspreading technique can maintain the same ultra-wideband signalbandwidth at a reduced data rate. In some variations, such a spreadingapproach may require a modification to the standard ultra-widebandMB-OFDM transmitter/receiver architecture. In some examples, thismodification can be implemented in a Software Defined Radio (SDR), FieldProgrammable Gate Array (FPGA) design, chipset, or the like. For chipsetimplementation using existing UWB chipsets, for example, the dataspreading may be done prior to data encryption, in the transmitter, andthe despreading may be done after data decryption, in the receiver.

In digital communications, symbol rate, which can also be known as baudrate and modulation rate, is the number of symbol changes, waveformchanges, or signaling events, across the transmission medium per timeunit using a digitally modulated signal or a line code. Each symbol canrepresent or convey one or several bits of data. In someimplementations, increasing data redundancy can include repeatingsymbols in the time and/or frequency domain. Repeating symbols in thetime and/or frequency domain can include adding a spreading sequence tothe symbols.

Many data communication systems use a modulated carrier signal totransfer data. For example, the frequency of a tone can be varied amonga set of possible values. In synchronous data communication systems, thefrequency of a tone can only be modified at fixed intervals. Thepresence of one particular frequency during one of these fixed intervalsconstitutes a symbol. In a modulated communication system, the term“modulation rate” can be used synonymously with the term “symbol rate.”

In radio-frequency communications, spread-spectrum techniques can bemethods by which a signal generated with a particular bandwidth can bespread in the frequency domain, resulting in a signal with a widerbandwidth. Spreading in the frequency domain can occur in technologiesthat aid in the security of the signal, increase resistance to naturalinterference of the signal, increase noise, increase jamming, to preventdetection of the signal or to limit power flux density. For example,spread spectrum can use a noise-like signal structure to spread anarrowband information signal over a wide band of frequencies. Areceiver in such a system can be configured to correlate the receivedsignals to retrieve the original information signal.

Frequency-hoping spread spectrum can include switching a carrier amongmany frequency channels when transmitting radio frequency signals. Insome variations, the switching of the carrier among many frequencychannels can be performed using a pseudorandom sequence that is known toboth the transmitter and the receiver of the radio frequencycommunication system. Interference and/or multipath null at a particularfrequency will likely only affect that particular frequency in thetransmission, allowing all other transmissions to be communicatedproperly. Where the same data is carried at multiple frequencies, a fulldata set can be received without the need to retransmit the data.

Time-hoping spread spectrum can include changing the transmission timeof a signal. The transmission time can be changed randomly by varyingthe period and duty cycle of a pulse (carrier) using a pseudo-randomsequence. Each part of the transmitted data communication will haveintermittent start and stop times.

Direct-sequence spread spectrum is a transmission method that modulatesthe signal. A modulation scheme can be employed to modulate a bitsequence. The bit sequence can be known as a Pseudo Noise code. ThePseudo Noise code can include a radio pulse that is much shorter induration (with a larger bandwidth) than the original signal. Themodulation of the signal scrambles and spreads the pieces of datathroughout the transmission.

In wireless communications, multipath is the phenomenon that results inradio signals reaching the receiver via two or more paths. Multipath cancause multipath interference, including constructive interference,destructive interference, and phase shifting. This can distort the datapackets transmitted on the signal.

To mitigate OFDM symbol degradation caused by multipath interference forthe extended range communications, the frequency hopping capability perFourier Frequency Transform (FFT) block is implemented on the UWBwaveform for the different data redundancy approaches.

For some patient care devices, the data rate required for wirelesstransmission of medical data from the patient care device to a userdevice of a medic or health provider can be less than 2.5 kbps. A lowdata rate, such as 2.5 kbps, can allow for the extension of thecommunications range by increasing the data redundancy in theultra-wideband (UWB) multi-band orthogonal frequency divisionmultiplexing (MB-OFDM) waveform, instead of increasing the transmissionpower. Methods for increasing data redundancy in the ultra-widebandwaveform can include repeating symbols in both the time and frequencydomain, adding a spreading sequence to the symbols, using coherentsymbol combining of the despread symbols before the error correctionprocess or majority logic detection of redundant bits after the errorcorrection process, or the like.

Coherent symbol combining provides the largest processing gain by addingthe despread chips of a symbol together before making a symbol decision.To achieve this higher processing gain, the signal is demodulated usinga coherent receiver that tracks the frequency and phase of the receiversignal. In addition, the receiver needs the added hardware complexity tosum the despreaded symbol components that are placed on different OFDMsubcarriers using frequency domain spreading (FDS) and/or acrossdifferent OFDM symbols using time domain spreading (TDS). The receivergiven in FIG. 4 and FIG. 5 use coherent symbol combining to maximize theprocessing gain of the receiver.

In error detection and correction, majority logic decoding is a methodto decode repetition symbols. The decoding of the repetition symbols canbe based on the assumption that the largest number of occurrences of aparticular symbol was the intended transmitted symbol. The receivergiven in FIG. 6 uses majority logic decoding to achieve processing gainfor the received signal.

FIG. 1 is an illustration of a system 100 having one or more featuresconsistent with the presently described subject matter. The system 100can include one or more patient care devices 102. A patient care device102 can be a wireless device capable of taking medical readings of apatient, control the administering of medications to a patient, or thelike. A patient care device 102 can include an electrocardiogram, aheartrate monitor, a blood oxygen monitor, a blood pressure monitor, athermometer, a glucose monitor, a syringe pump, a scale, a temperatureregulator, or the like.

The patient care device 102 can include a data generator 104. The datagenerator 104 can include one or more components of the patient caredevice 102 that is configured to monitor one or more of a state of apatient, send an alert based on a patient failing condition, a state ofthe patient care device 102, or the like. The data generator 104 can beconfigured to generate data associated with the monitoring of the one ormore of a state of a patient, a state of the patient care device 102, orthe like.

The patient care device 102 can include a chipset 106. The chipset 106can be configured to perform one or more of the functions of thepresently described subject matter. For example, the chipset 106 can beconfigured to support data spreading, data encryption, data decryption,data modulation, carrier signal generation, or the like.

The patient care device 102 can include a transceiver 108. Thetransceiver 108 can include a data transmitter and/or a data receiver.The transceiver 108 can be configured to generate a radio waveform basedon an input from the chipset 106.

The patient care device 102 can include an antenna 110. The antenna 110can be configured to convert electrical power received from thetransceiver 108 into radio waves, and vice versa. In transmission, thetransceiver 108 can supply a radio waveform to one or more terminals ofthe antenna 110. The antenna 110 can be configured to radiate the energygenerated by the transceiver 108 in electromagnetic waves. In reception,the antenna 110 can be configured to intercept at least part of thepower of an electromagnetic wave and produce a voltage at one or moreterminals of the antenna 110. The antenna 110 and/or the transceiver 108can include an amplifier configured to amplify the voltage produced atthe one or more terminals of the antenna 110.

The system 100 can include one or more user devices 112. The user device112 can be a device used by a medical provider. The user device 112 canbe configured to receive data from one or more patient care devices 102.The user device 112 can include one or more display devices configuredto present information to a user of the user device 112.

The user device 112 can comprise an antenna 114. The antenna 114 can beconfigured to detect at least a part of the power of electromagneticwaves generated by the antenna 110 of the patient care device(s) 102.The antenna 112 can perform similar functions as the antenna 110 of thepatient care device 102. The user device 112 can comprise a transceiver116. The transceiver 116 can perform one or more functions similar tothe transceiver 108 of the patient care device 102. The user device 112can comprise a chipset 118. The chipset 118 can be configured to performone or more similar functions to the chipset 106 of the patient caredevice 102. The user device 112 can include a data generator 120. Thedata generator 120 can be configured to convert data from the chipset118 into data that can be presented on a display of the user device 112.The data generator 120 can be configured to receive data representativeof an input or instruction from the user of the user device 112 and passthe data to the chipset 118 for manipulation and eventual transmissionby the transceiver 116.

In some variations, the patient care device 102 can comprise a secondantenna 122. The second antenna 122 can comprise a higher gain antenna.The higher gain antenna may be used only during reception of signals,for example, signals transmitted by the user device 112. The patientcare device 102 may comprise a radio frequency switch 124. The radiofrequency switch 124 can be configured to cause the transceiver 108 toconnect to the appropriate antenna for transmission and reception pathsof the patient care device 102. Similarly, the user device 112 cancomprise a second antenna 126. The second antenna 126 can comprise ahigher gain antenna used only during reception of signals, for example,signals transmitted by one or more patient care devices 102. The userdevice 112 can comprise a radio frequency switch 128 configured to causethe transceiver 116 to connect to the appropriate antenna fortransmission and reception paths of the user device 112. In somevariations, the patient care device 102 and the user device 112 cancomprise multiple transceivers, one for each antenna.

Two transceivers in the user device 112 can enable the user device tosetup two networks on different independent UWB channels forimplementing independent higher and lower data throughput channels forconnection with various devices. The higher data throughput channelsupports video transmissions over shorter communications distances. Thelower data throughput supports lower data throughput transmissions fromand to multiple patient care devices 102 over longer communicationsdistances with higher channel interference and multipath channeldegradations.

Although the components of the patient care device 102 and the userdevice 112 are illustrated as separate components, this is forillustrative purposes only. The components of the patient care device102 and the user device 112 can be provided, for example, as a singleintegrated circuit, as two or more integrated circuits, as separateintegrated circuits, software defined radio architecture, FieldProgrammable Gate Array (FPGA) design, a combination of hardware andsoftware design elements or the like.

FIG. 2 is an illustration of a signal 200 generated by a device havingone or more features consistent with the presently described subjectmatter. FIG. 2 shows a typical ultra-wide band (UWB) multi-bandorthogonal frequency-division multiplexing (MB-OFDM) transmit signalhaving two different multipath delay conditions with respect to thedirect path, the direct path being, for example, the path taken directlybetween the patient care device 102 and the user device 112. The signal200 may be subject to multipath delays. For multipath delays less than60 ns, referred to multipath delay within an OFDM symbol 202, themultipath signal can fall within the zero padding section of the signal200. For multipath delays greater than 312.5 ns, referred to multipathdelay across OFDM symbols 204, the multipath signal can fall with theboundary of the next adjacent OFDM symbol. As shown in FIG. 2, frequencyhopping to a different carrier frequency (corresponding to a differentUWB channel) can place the multipath signal, delayed greater than 312.5ns, at a different carrier frequency (corresponding to a different UWBchannel) than the direct path, thus enabling the receiver to filter outthe multipath signal. For the multipath delay less than 60 ns, thechannel estimation algorithm can be configured to determine the channeleffects and can maximize the receiver detection using both the directand multipath signal. In addition, data spreading can be applied to theUWB waveform if it supports the required data throughput to helpmitigate the multipath degradation.

For multipath delays greater than 60 ns, the channel estimation can beconfigured to operate on the direct path signal only, and frequencyhopping can be used to cause the symbol delayed greater than 60 ns to betransmitted on a different carrier frequency than the direct path, thusenabling the receiver to filter out the multipath signal. If frequencyhopping did not occur, for multipath delays greater than 60 ns, theprevious OFDM symbol may be in the same detection window as the presentOFDM symbol. If these OFDM symbols operated at the same carrierfrequency (UWB channel), the previous OFDM symbol would interfere anddegrade the detection of the present OFDM symbol. However, since theseOFDM symbols are at different carrier frequencies, filtering providesrejection of the previous OFDM symbol to mitigate receiver degradation.On such situations, the channel estimation algorithm can provide nosignal improvement by using the multipath signal.

Table 1 shows examples of available frequency channels forultra-wideband band group 3, 4, 5 and 6. For each UWB channel, thesignal bandwidth is 528 MHz, which correspond to the difference betweenthe upper and lower channel frequency. In addition, the centerfrequencies are separated by 528 MHz. In the example shown in Table 1,three channels are available for use in ultra-wideband band groups 3, 4and 6, while only two frequency channels are available in ultra-widebandband group 5. Table 2 shows single or frequency hopping channels withina band group, defined by the Time Frequency Code (TFC). The UWB bandnumbers defining the channels used for the hopping sequences are relatedto the channels defined in Table 1.

TABLE 1 Band Group Operational Frequencies UWB UWB Channel Frequencies(MHz) Band Band Center Lower Upper Group Number Freq Freq Freq 3 7 66006336 6864 8 7128 6864 7392 6 9 7656 7392 7920 4 10 8184 7920 8448 118712 8448 8976 12 9240 8976 9504 5 13 9768 9504 10032 14 10296 1003210560

TABLE 2 UWB Single or Hopping Channels Band Single Channel or ChannelHopping Sequence Using UWB Band Numbers Versus TFC Number Group 1 2 3 45 6 7 8 9 10 3 (7, 8, 9, 7, (7, 9, 8, 7, (7, 7, 8, 8, (7, 7, 9, 9, 7 8 9(7, 8, 7, 8, (7, 9, 7, 9, (8, 9, 8, 9, 8, 9) 9, 8) 9, 9) 8, 8) 7, 8) 7,9) 8, 9) 4 (10, 11, 12, (10, 12, 11, (10, 10, 11, (10, 10, 12, 10 11 12(10, 11, 10, (10, 12, 10, (11, 12, 11, 10, 11, 12) 10, 12, 11) 11, 12,12) 12, 11, 11) 11, 10, 11) 12, 10, 12) 12, 11, 12) 5 13 14 (13, 14, 13,14, 13, 14) 6 (9, 10, 11, (9, 11, 10, (9, 9, 10, (9, 9, 11, 9 10 11 (9,10, 9, (9, 11, 9, (10, 11, 10, 10, 11) 9, 11, 10) 10, 11, 11) 11, 10,10) 10, 9, 10) 11, 9, 11) 11, 10, 11)

Channel hopping can mitigate receiver degradation introduced bymultipath signals for an extended range communication. In somevariations, the robustness of the existing UWB MB-OFDM signal can beincreased to enable an extended communication range. In some examples,the link margin can be increased by increasing the transmit power and/orantenna gain. The link margin is the difference between a receiver'ssensitivity (i.e., the minimum received power at which the receiver willstill work) and the actual received power. Increasing the antenna gaincan result in no additional power consumption of a transceiver, such astransceiver 108 of the patient care device 102 illustrated in FIG. 1.

An increase in transmit power can increase power consumption of thetransceiver, such as transceiver 108 of the patient care device 102illustrated in FIG. 1. Using increased antenna gain, increased transmitpower or both increased antenna gain and increased transmit power canresult in the transmit radio frequency power level of a transceiver,such as transceiver 108, being increased. This increase in radiofrequency transmit power can degrade the low probability of detection(LPD) and the low probability of interception (LPI) of the ultra-wideband signal provided by ultra-wide band waveforms. Thus, making it morelikely that the signal can be detected and intercepted by a third-party.To mitigate this degradation in low probability of detection (LPD) andlow probability of interception (LPI) performance, the ultra-widebandsystem, such as system 100 illustrated in FIG. 1, can be configured touse a second higher gain antenna that is only used during reception ofdata, such as antenna 122, of the patient care device 102, and/orantenna 126, of the user device 112, illustrated in FIG. 1. The radiofrequency switches, 124 and 128, can be configured to facilitateconnection to the appropriate antenna for separate transmit and receivepaths.

Use of additional hardware components in a communication system, such asusing the second antennas 122 and 126 and radio frequency switches 124and 128, can cause an increase in interference and/or signal degradationwithin the network elements. To account for the increase in interferenceand/or signal degradation, additional data redundancy can be added tothe UWB MB-OFDM signal. In some examples, additional redundancy can bepossible due to the data rate and packet size of data transmitted usingthe UWB MB-OFDM signals. For example, the data rate and packet size ofmedical data generated by a patient care device(s) 102 can be relativelylow compared to the capabilities of the communication network on whichthe patient care device(s) 102 and the user device 112 communicate.

In some examples, additional data redundancy can be provided byexpanding the number of repeated symbols in both the time and frequencydomains. Table 3 shows examples, in the bottom two rows, of the lowesttwo data rates that can be implemented for traditional UWB MB-OFDMwaveforms. Table 3 is exemplary and shows the data rates for theECMA-368 standard. The presently described subject matter can be appliedto other waveforms and is not limited to the ECMA-368 standard.

TABLE 3 Added Data Redundancy Redundant Burst Coded bits Info Data CodeCoding Data Rate per 6 bits per Modulation Rate TDS FDS (Mbps) ModSymbol Symbol QPSK 1/3 20 4 2.67 15 5 QPSK 1/3 20 2 5.33 30 10 QPSK 1/38 2 13.33 75 25 QPSK 1/3 2 2 53.33 300 100 QPSK 1/2 2 2 80.00 300 150

Lower data rates can be generated by a system, such as system 100illustrated in FIG. 1, by increasing the time domain spreading (TDS) andfrequency domain spreading (FDS). For time domain spreading, a system,such as system 100, can be configured to place redundant coded bits inthe time domain at different OFDM symbols. For frequency domainspreading, a system, such as system 100, can be configured to placeredundant coded bits on different OFDM subcarriers. In some examples, anultra-wide band transmitter, such as included in transceivers 108 and116, can provide the added data redundancy. An ultra-wideband receiver,such as included in transceivers 108 and 116, can be configured tocoherently combine the redundant symbols to increase the detectionperformance of the receivers.

Providing additional data redundancy means that the same symbol istransmitted repeatedly which can result in an increased ability forthird-parties to detect and/or intercept the ultra-wideband signals.

In some examples of the presently described subject matter, additionaldata redundancy can be provided, without transmitting the same redundantdata multiple times. For example, a system, such as system 100, can beconfigured to use direct sequence spreading to encode data bits prior tothe OFDM modulation process. The OFDM modulation randomizing therepeated symbols such that any attempt to detect and/or intercept theultra-wideband signal will result in two separate detected signals forthe same symbol and deciphering such detected signals will be morechallenging.

For another example, a system, such as system 100, can be configured touse direct sequence spreading to encode data bits at different locationswithin the transmitter processing enabling the system to used exitingultra-wideband chipsets or modified architectures using new chipsets, asoftware defined radio architecture, Field Programmable Gate Array(FPGA) design, combination of hardware and software design elements orthe like. One direct spreading approach places the direct sequencespreading after the data encryption, data error encoding andinterleaving processes as shown in a system, such as system 400. Anotherdirect spreading approach places the direct sequence spreading after thedata encryption and data error encoding as shown in a system, such assystem 500. Moving the direct spreading before the data encryption, dataerror encoding and interleaving processes is shown in a system, such assystem 600. For a system, such as system 600, direct sequence spreadsthe data first. The spread data, known as chips, are processed by thechip encryption, chip error encoding, and chip interleaving before beingplaced on the MB-OFDM subcarriers. The direct sequence spreading for allthree different system configurations causing the same symbols to berandomly changed which will result in the same repeated symbol appearingdifferently to a detector and/or interceptor of the ultra-widebandsignal. Direct sequence spreading systems can increase the signalbandwidth by spreading lower rate data with a higher rate spreadingsequence.

FIG. 3 shows an example of a typical QPSK direct sequence spreading donein the time domain on a single carrier frequency. FIG. 3 shows the QPSKdirect sequence data spread spectrum system 300 having one or morefeatures consistent with the presently described subject matter. The toplevel QPSK direct sequence data spread spectrum system 300 is a typicaldirect spreading modulator for a Quadrature Phase Shift Keyed (QPSK)system, where in-phase (I) and quadrature (Q) spreading sequences can begenerated by either single or separate spreading code generators 302.The in-phase (I) spreading sequences can modulate the Cosine componentof the waveform and the quadrature (Q) spreading sequences can modulatethe Sine component of the waveform. FIG. 3 shows a typical QPSK DirectSequence Spreading Modulator. The I/Q chip rate is N times faster thanthe I/Q data rate, thereby increasing the signal bandwidth. The chiprate is the number of chips per second used in the spreading signal. Thedata, spreading code, and spread signals are non-return to zero (NRZ)signals, resulting in +1 or −1 values. A carrier frequency can begenerated by a signal generator 304. For this spreading system, the Iand Q spread signals can be up-converted to the carrier frequency(f_(o)) by the quadrature mixer operation. This operation corresponds toa single carrier system unlike the UWB MB-OFDM system, which consists of100 data subcarrier signals, that require an I and Q spreading sequencefor each data subcarrier, which can be generated by either a singlespreading code generator or separate spreading code generators.Placement of an inphase and quadrature spread data on each of thesubcarriers of an orthogonal frequency division multiplexing (OFDM) dataspread spectrum signal can be implemented using this same approach thatplaces the direct spread data onto a single subcarrier frequency, whereeach subcarrier that is using direct sequence spreading requires thismodulation structure. As shown in all three OFDM configurations given inFIG. 4, FIG. 5, and FIG. 6, the Inverse Fast Fourier Transform (IFFT)provides an efficient algorithm for placing the direct spread data ontothe subcarriers. The IFFT generates the discrete OFDM waveform over anOFDM symbol period by converting the discrete Fourier Transformdeveloped by placing the QPSK direct spread data as an amplitude andphase modulation on each subcarrier. For QPSK direct spreading, onlyphase modulation is required to implement the direct sequence dataspreading, since the direct spread data changes the phase of thesubcarrier signal. This subcarrier phase change by the spread data isdemonstrated by examining the typical QPSK Direct Sequence SpreadingModulator given in FIG. 3.

For the transmitter, the multiplication operation corresponding to Idata multiplied by I spreading code and Q data multiplied by Q spreadingcode for each subcarrier can be simply performed by a binary multiplier(an exclusive-or operation), resulting in 200 binary multiplieroperations; 2 multiplication for each of the 100 data subcarriers forQPSK spreading on each OFDM subcarrier. In some variations, the numberof binary multipliers required can be reduced to a lower number byoperating the spreading operation at a higher clock rate. As shown inFIG. 3, the typical QPSK direct sequence spreading can be done in thetime domain. The multiple data subcarrier signals of the UWB OFDM signalcan provide the capability to spread in the time domain, the frequencydomain, or the time domain and the frequency domain. Spreading in thetime domain places spread data across multiple OFDM symbols, whilespreading in the frequency domain places spread data across multiplesubcarriers in the same OFDM symbol.

A receiver in the present system can comprise components configured toperform a despreading operation and an accumulator to sum up thedespread signal for data detection. The accumulator can perform itsoperations after the components configured to perform the despreadingoperation. Using QPSK subcarrier modulation can require two sets (I & Q)of operations. The two sets of operations can include despreading,accumulation and data detection for each subcarrier. To obtain thecoherent processing at the receiver, the despreading and accumulatorprocessing can require multi-level processing. The despreadingmulti-level processing can be reduced by using multi-level exclusive-orgates to multiple two's (2's) complement numbers. Two's complement is anoperation performed on binary numbers. The two's complement of an N-bitnumber is defined as the complement with respect to 2^(N); this is alsoequivalent to taking the ones' complement and then adding one, since thesum of the number and its ones' complement is all 1 bits. The decisionon the accumulated despread signal results in the detection of thecorresponding received data signal for each subcarrier. By operating ata higher clock rate, the number of hardware elements required toimplement the despreading, accumulation and data detection can bereduced.

FIG. 4 gives a top-level block diagram of a system 400 having one ormore features consistent with the presently described subject matter.The system 400 provides an orthogonal frequency division multiplexingdata spread spectrum system which places the direct sequence spreadingafter the data encryption, data error encoding and interleavingprocesses. The system 400 can be configured to perform subcarrier directsequence spreading using a non-linear spreading sequence generator 402for improved transmission security (TRANSEC) over a linear spreadingsequence. The IFFT mapping component 408 provides the capability tospread in the time domain, the frequency domain, or the time domain andthe frequency domain by the mapping of the spread data to the OFDMsubcarriers for each OFDM symbol. The system 400 shows a transmitter 404and a receiver 406.

In some exemplary variations, in the transmitter 404, the I and Qsignals out of the 128 point Inverse Fast Fourier Transform (IFFT)operate at the same sampling rate of 528 Msps, which provides asubcarrier frequency spacing of 4.125 MHz. Table 4 gives the mapping ofsubcarriers for the OFDM signal of this exemplary variation. The mappingof subcarriers for the OFDM signal, in Table 4, includes null (nosubcarrier modulation) guard, pilot and data subcarriers. Using QPSKspreading modulation, the OFDM signal provides 200 chips of spreadingcapability (100 chips for each I and Q signals) per OFDM symbol. Asshown, the spreading does not impact the subcarrier frequency spacing(4.125 MHz) or UWB channel bandwidth (528 MHz), but requires the spreaddata to be properly mapped into the IFFT. The IFFT mapping can beperformed by an IFFT mapping component 408, for example. Althoughillustrated as a separate component, the IFFT mapping component 408 canbe integrated with one or more components of the transmitter 404 and/orreceiver 406.

TABLE 4 Subcarrier Mapping Symmetric FFT FFT Subcarrier SubcarrierSubcarrier Index Index Type −63 65 Null −62 66 Null −61 67 Guard −60 68Guard −59 69 Guard −58 70 Guard −57 71 Guard −56 72 Data −55 73 Pilot−54 74 Data −53 75 Data −52 76 Data −51 77 Data −50 78 Data −49 79 Data−48 80 Data −47 81 Data −46 82 Data −45 83 Pilot −44 84 Data −43 85 Data−42 86 Data −41 87 Data −40 88 Data −39 89 Data −38 90 Data −37 91 Data−36 92 Data −35 93 Pilot −34 94 Data −33 95 Data −32 96 Data −31 97 Data−30 98 Data −29 99 Data −28 100 Data −27 101 Data −26 102 Data −25 103Pilot −24 104 Data −23 105 Data −22 106 Data −21 107 Data −20 108 Data−19 109 Data −18 110 Data −17 111 Data −16 112 Data −15 113 Pilot −14114 Data −13 115 Data −12 116 Data −11 117 Data −10 118 Data −9 119 Data−8 120 Data −7 121 Data −6 122 Data −5 123 Pilot −4 124 Data −3 125 Data−2 126 Data −1 127 Data 0 0 Null 1 1 Data 2 2 Data 3 3 Data 4 4 Data 5 5Pilot 6 6 Data 7 7 Data 8 8 Data 9 9 Data 10 10 Data 11 11 Data 12 12Data 13 13 Data 14 14 Data 15 15 Pilot 16 16 Data 17 17 Data 18 18 Data19 19 Data 20 20 Data 21 21 Data 22 22 Data 23 23 Data 24 24 Data 25 25Pilot 26 26 Data 27 27 Data 28 28 Data 29 29 Data 30 30 Data 31 31 Data32 32 Data 33 33 Data 34 34 Data 35 35 Pilot 36 36 Data 37 37 Data 38 38Data 39 39 Data 40 40 Data 41 41 Data 42 42 Data 43 43 Data 44 44 Data45 45 Pilot 46 46 Data 47 47 Data 48 48 Data 49 49 Data 50 50 Data 51 51Data 52 52 Data 53 53 Data 54 54 Data 55 55 Pilot 56 56 Data 57 57 Guard58 58 Guard 59 59 Guard 60 60 Guard 61 61 Guard 62 62 Null 63 63 Null 6464 Null

In some variations, IFFT mapping provides time domain spreading of 1, 2or 4 and frequency domain spreading of 5, 10, 20 and 25. Table 5 showsthe burst rates for these different time and frequency domain spreadingvalues. Since the subcarrier frequency spacing of 4.125 MHz is notmodified, the increase in time and frequency domain spreading results ina lower burst rate, as shown in Table 5. Table 5 shows that increasingthe time and frequency domain spreading increases the direct spreadingprocessing gain.

TABLE 5 QPSK Spreading Burst Rates Data Code I/Q Spreading (Chips) TotalChips per Coded bits per Info bits per Burst Data Processing ModulationRate Time Freq 6 Mod Symbol 6 Mod Symbol 6 Mod Symbol Rate (Mbps) Gain(dB) QPSK 1/3 4 25 1200 12 4 2.13 20.00 QPSK 1/3 4 20 1200 15 5 2.6719.03 QPSK 1/3 4 10 1200 30 10 5.33 16.02 QPSK 1/3 4 5 1200 60 20 10.6713.01 QPSK 1/3 2 25 1200 24 8 4.27 16.99 QPSK 1/3 2 20 1200 30 10 5.3316.02 QPSK 1/3 2 10 1200 60 20 10.67 13.01 QPSK 1/3 2 5 1200 120 4021.33 10.00 QPSK 1/3 1 25 1200 48 16 8.53 13.98 QPSK 1/3 1 20 1200 60 2010.67 13.01 QPSK 1/3 1 10 1200 120 40 21.33 10.00 QPSK 1/3 1 5 1200 24080 42.67 6.99

In the example shown in Table 5, the first row, I and Q spreading chipsare placed in four (4) different OFDM symbols using twenty five (25)subcarriers per OFDM symbol. This spreading configuration corresponds to100 chips per coded bit (I or Q bit). Since there are 1200 chips in six(6) OFDM symbols, the number of coded bits within these 6 OFDM symbolsis 12. For a coding rate of ⅓, the number of information bitstransmitted with the 6 OFDM symbol corresponds to 4 bits. The otherentries of Table 5 are determined by using one or more of the followingrelationships. By multiplying the time and frequency spreading valuestogether, the number of chips per coded I or Q bit can be determined.Dividing the total 1200 chips per 6 OFDM symbols by the number of chipsper coded bit gives the number of coded bits per 6 OFDM symbols.Multiplying the number of coded bits per 6 OFDM symbols by the codingrate provides the number of information bits per 6 OFDM symbols. Bydividing the number of information bits per 6 OFDM symbols by the timelength of 6 OFDM symbols (1.875 us) provides the burst data rate. Asshown in Table 5, the selection of different time and frequencyspreading produces burst data rates from 1.07 to 21.33 Mbps. The lowerburst data rates provide the higher processing gain by increasing thenumber of chips per bit, which results in a lower receiver sensitivitylevel.

Translation of the OFDM subcarriers to the desired transmission signalfrequency range can be generated by a carrier signal generator 410. IFFTmapping with no time spreading, maps the spread data chips to asubcarrier that is separated by 100 divided by the frequency spreadingvalue. For example, row 10 of Table 5, maps the spread data to 20 of the100 subcarrier with a subcarrier separation of 5 versus row 12 of Table5, which maps the spread data to 5 of the 100 subcarrier with asubcarrier separation of 20. When time spreading is added to thespreading operation, the frequency mapping is shifted. For timespreading of two (2), the frequency mapping within the OFDM symbol willbe shifted differently over two OFDM symbols with this pattern repeatingitself. For time spreading of two (2), the first OFDM symbol uses thefrequency spreading frequency separation based on the frequencyspreading value. The second OFDM symbol will shift the frequency mappingby 2 subcarriers for frequency spreading of 20 and 25, 5 subcarriers forfrequency spreading of 10, and 20 subcarriers for frequency spreading of5. Increasing the time spreading to four (4), results in four differenttime shifts that are repeated. The first OFDM symbol uses the frequencyspreading frequency separation based on the frequency spreading value.The second, third and fourth OFDM symbols will shift the frequencymapping by 1 subcarrier for each symbol for frequency spreading of 20and 25, 2 subcarriers for each symbol for frequency spreading of 10, and5 subcarriers for each symbol for frequency spreading of 5. After foursymbols this frequency shift will repeat itself.

The Fast Fourier Transform (FFT) output mapping places both the receivedI and Q signals into the proper sequence for despreading andaccumulation for data detection. This FFT mapping algorithm requiresadded complexity to the design. By placing the received I and Qsubcarrier signals into a memory element, proper control of theaddressing bus can be used to proper sequence the received signals fordespreading of the subcarriers. After despreading, the despread data isdeinterleaved followed by data error decoding and correction, thedecoded bits are decrypted to provide the PCD information data for apatient care device (PCD) transmission to the user device (UD).

The presently described direct sequence spreading approach can providecoherent detection performance despite additional hardware complexity.In the presently described examples, processing gain for the coherentdetection is equal to 10*log 10(N) dB, where N is the number ofspreading chips for the I/Q signal. Table 5 shows that the processinggain between 7 and 20 dB can be provided using this approach. For freespace path loss, a 6 dB increase in processing gain results in adoubling of the communications range. From Table 3, the lowest burstrate for the existing OFDM system with redundant symbols and nospreading provides a processing gain of 6 dB with the time and frequencyredundancy equal to 2 for each domain. The increase processing gain overthe existing lowest burst rate provided by spreading is between 1 and 14dB, which results in a communications range increase of 1.12 to 5.0times.

FIG. 5 shows a top level block diagram of a system 500 having one ormore features consistent with the presently described subject matter.The system 500 may have one or more elements that are similar to one ormore elements of the system 400. In some examples, the transmitter 504and the receiver 506 of the system 500 may have less hardware complexitycompared the transmitter 404 and the receiver 406 of system 400. Forexample, for the transmitter 504 in the system 500, the data spreadingoperation 508 can be performed between the data error encoding operation510 and the interleaving operation 512. For the receiver 506 in thesystem 500, the data despreading operation 514 can be performed betweenthe de-interleaving operation 516 and the data error decoding operation518. For the system 500, a more typical data spreading/despreadingoperation can be performed. The chip interleaver can be configured tospread the chips across the OFDM subcarriers. To obtain the fullprocessing gain, the number of quantization levels into the chipde-interleaver operation 516 needs to be greater than one for softdecision despreading. Using hard decision despreading effectivelyreduces the processing, but simplifies the hardware complexity. Theencoded data decision out of the despreading operation can be mappedinto a soft decision for improved data error correction in the dataerror decoding.

FIG. 6 shows a top level block diagram of a system 600 having one ormore features consistent with the presently described subject matter.The system 600 can be configured to perform top level data expansionusing spreading. To minimize hardware impact to the ultra-widebandtransmitter 604, especially for operation with an existingultra-wideband (UWB) chipset, the data spreading operation 608 can beplaced before the data encryption operation 610 on the transmitter 604.To minimize hardware impact to the ultra-wideband receiver 606, the datadespreading operation 612 can be placed after the data decryptionoperation 614. In some variations, a data redundancy operation (e.g.,generating multiple repeats of the same bit) can be implemented.However, in some implementations, such data redundancy operations couldcompromise the encryption operation. The data can be spread using anon-linear sequence generator 616. The non-linear sequence generator 616can be configured to change the starting location of the sequence onevery transmission to avoid compromise of the encryption operation. Insome examples, the non-linear sequence generator 616 can be configuredto change the starting location of the sequence according to apredefined pattern.

The spreading operation performed by the data spreader 608 can beconfigured to convert the input data bit into an N-chip sequence thatgets inverted or non-inverted depending on the data bit value. One ormore operations, including encryption, error encoding, interleaving,IFFT mapping, subcarrier quad mixing, or the like can be performed afterthe data spreading by the transmitting device, for each spread chip. Oneor more operations, including subcarrier quad mixing, FFT mapping, chipdetection, decoding, decrypting, or the like can be performed beforedata despreading by the receiving device, for each chip of the spreaddata.

In some variation, the configuration of system 600 can reduce thehardware complexity compared to other systems. In some examples, thesystem 600 may cause degradation in the processing gain by the singlequantization level despreading detection of the signal. This singlequantization level despreading detection can perform majority logicdetection on the despread data. The data detection can handle N/2−1 chiperrors (where N equals the number of chips per data bit) and stillprovide a correct data detection. In examples where the system 600provides enhanced data performance outside of the transceiverarchitecture, a spread cyclic redundancy check (CRC) on the data can tobe added to the data transmitter 604 and the data receiver 606 forverification of a properly received packet.

FIG. 7 is a process flow diagram showing a process 700 having one ormore features consistent with the presently described subject matter.Process 700 can be performed by one or more processors having one ormore features consistent with the present description.

At 702, data can be generated. In some variations, data can be generatedby one or more inputs of a patient care device. For example, where thepatient care device is a thermometer, the one or more inputs of thepatient care device may be a temperature sensor. The temperature sensorcan be configured to generate a signal having an indication of atemperature. Where the patient care device is an electrocardiogram, theinput of the patient care device may be one or more electrocardiogramleads configured to generate signals associated with a patient's heartand/or other vital systems.

At 704, a variable spreading sequence can be generated for spreading thedata. The spreading sequence is used to direct sequence spread the data.The spreading sequence generator can be a pseudo-random spreadingsequence generator or nonlinear spreading sequence generator. Thepseudo-random order or nonlinear spreading generator parameters can beknown by the transmitter and the receiver of a communication system.

At 706, the spread data having been spread by the variable spreadingsequence can be encrypted, error encoded, and interleaved. Encryptioncan include encoding data in such a way that only authorized parties canaccess it. The encryption can be a symmetric-key encryption scheme. Thetransmitting device and the receiving device can have the same sharedsecret key to decrypt the data. The encryption can be a public-keyencryption scheme. The encryption key can be published for anyone to useand encrypt messages. However, only the receiving party can be grantedaccess to the decryption key that enables messages to be read. The errorencoding processes encodes the message in a redundant way by using anerror-correcting code for correction of reception errors at thereceiver. The error code parameters are known by the transmitting andreceiving devices. Error encoding approaches include the convolutionalencoding using the Viterbi algorithm, Turbo codes, cyclicerror-correcting codes using Reed-Solomon codes, or the like.Interleaving reorders the spread data to be transmitted so thatconsecutive spread data chips are distributed over a larger sequence ofspread data chips to reduce the effect of burst errors. The interleavingprocess performed in the transmitter is known at the receiver, so thede-interleaving process provides the proper time order of the spreaddata for the following receiver processing.

At 708, the IFFT mapping of the spread data to the OFDM subcarrierswithin the OFDM symbols generates an ultra-wideband (UWB) waveform withdirect spread data. IFFT mapping of the spread data to the subcarriersand OFDM symbols can generate time-domain spreading, frequency-domainspreading, time and frequency domain spreading, or the like.

At 710, the carrier signal generator translates the direct sequencespread OFDM subcarriers to the desired transmission signal frequencyrange.

At 712, the direct sequence spread ultra-wideband (UWB) signal can betransmitted. The direct sequence spread (UWB) signal can be transmittedby a transmitter in the transmitting device, such as a patient caredevice, user device or the like.

In some variations, the user device(s) and/or the patient care device(s)of the presently described ultra-wideband network can be configured tocontrol the transmission power of the signals transmitted between theuser device(s) and/or the patient care device(s).

The presently described addition of the data spreading to theultra-wideband waveform can increase the processing gain of the signalthat can be used to reduce the radio frequency (RF) transmit power forshort communication links that do not need the extended communicationsrange or high data rate capability. By reducing the RF transmit power,power consumption and heat generation within the patient care device(PCD) can be reduced, resulting in a longer battery life. In addition,the lower RF transmit power level can improve the Low Probability ofIntercept/Low Probability of Detection (LPI/LPD) performance by drivingthe signal lower into the noise floor. For example, for communicationswithin a transport vehicle or treatment area, the ultra-wideband networkcan include short range communication elements such as patient caredevices and user devices that collect and monitor medical data of thepatient. The medical data of the patient can be supplied by the patientcare devices.

For short-range communications operating at a low data rate, thewideband and narrowband signal strength measurements of the receivedultra-wideband data signal power provide an estimation of the receivedsignal strength. By comparing this received signal strength estimationagainst the minimum operational signal strength reference for the dataspread signal with an additional controllable signal margin parameter(typical range of 2 to 5 dB), the recommended reduction in RF transmitpower can be determined.

To mitigate small changes in RF transmit power levels that do notsignificantly reduce power consumption or improve LPI/LPD significantly,a power reduction step size of 3 dB or greater may be implemented. Tosupport the maximum processing gain of 20 dB provided by the highestdata spreading, the power reduction can support a range of 3 to 21 dB.Before communicating the recommended RF transmit power from the receiverto the transmitter, the receiver can be configured to check the Viterbierror correction across the data packet to verify the reliability of theexisting communications link. A high number of error corrections canresult in recommending no change in the RF transmit power. At thepatient care device, the recommended RF transmit power reduction levelcan be sent as an attachment to the patient medical data. At the userdevice, the recommended RF transmit power reduction level can be sent asan attachment to the acknowledgement packet to one or more received datapackets.

One non-limiting exemplary advantage of the presently described subjectmatter can be the increased range of ultra-wideband communicationswithout increasing the transmit power, by taking advantage of the lowdata transmit rates of medical data transmitted by patient care devices.

Another non-limiting exemplary advantage of the presently describedsubject matter is reduced power consumption due to the low data rateover the ultra-wideband communication network. The patient care deviceand the user device can be configured to reduce the transmission poweruntil signal quality falls below a predetermined threshold value. Thepatient care device and/or the user device can be configured todetermine the bit rate of the data to be transmitted and select atransmission power level for that bit rate.

The presently described subject matter can relate to estimatinginterference in a communication network. In some variations, thepresently described subject matter can be applied to multiple devices inthe communication network. For example, a communication network maycomprise multiple patient care devices, such as patient care device 102illustrated in FIG. 1. The multiple patient care devices can beconfigured to communicate with a user device, such as user device 112illustrated in FIG. 1. In some variations, a communication network cancomprise multiple user devices. The multiple user devices and/or themultiple patient care devices can be configured communicate with oneanother in a communication network.

In one aspect, an estimation of interference at an ultra-wideband (UWB)receiver can be determined. The ultra-wideband receiver can be part of anode operating in an ultra-wideband network. The node can comprise atransmitter and/or a receiver. The transmitter and/or receiver can beseparate components within the node or can be part of the samecomponent, such as a transceiver. The estimation of interference can bedetermined using an interference estimation algorithm that uses thewideband radio frequency (RF) received signal estimation and narrowbandorthogonal frequency division multiplexing (OFDM) subcarrier levels ofan ultra-wideband waveform combined with the number of symbol errorcorrections in the decoding processes to estimate the interference levelbetween a transmitting device and a receiving device. Since theinterference level within an ultra-wideband network can be significantlydifferent across the ultra-wideband nodes, the interference levels ateach node can be estimated and transmitted back to a master node fordetermination of the interference level across at least a portion of thenetwork. The master node can be configured to process the interferencelevels across at least a portion of the ultra-wideband network alongwith its own interference level. The master node can be configured toprocess this interference data and determine if an operational channel,on which the ultra-wideband communication is being transmitted, needs tobe changed in order to reduce the amount of interference in theultra-wideband communication network.

In response to a determination, by the master node, that using adifferent channel to communicate is required to reduce interferenceacross the ultra-wideband network, the master node can be configured totransmit channel change information to one or more slave nodes connectedto the master node. The slave nodes can be configured to acknowledge thereceipt of the channel change message before moving to the selectedchannel.

In some variations, an ultra-wideband network can be used fortelemedicine. A master node, when used in telemedicine, can be a userdevice (UD) close area medical integration technology (CAMIT) module(UDCM). The UDCM can be connected to a user device platform. The userdevice platform can include one or more of a tablet, a laptop, anothercomputing device, or the like. In some variations, the user device canprovide the computing power to determine the interference estimationwithin the ultra-wideband network. In some examples, one or more slavenodes connected to a UDCM can include patient care device CAMIT modules(PCDCMs) connected to patient care devices (PCDs) and/or other UDCMsconnected to user devices that are slaves to the master mode within theultra-wideband network. The PCDCMs and/or slave UDCMs can be configuredto estimate an amount of interference at their location and communicatethe amount of estimated interference level back to the master UDCM.

FIG. 8 is a schematic illustration of a system 800 having one or moreaspects of the presently described subject matter. The system 800 caninclude an ultra-wide band network 802. In some variations, theultra-wideband network 802 can include a plurality of devicescommunicating using one or more shared communication channels. As anexample, the plurality of devices can include a master user device 804,one or more slave user devices 806, and one or more patient care devices808-814. The patient care devices 808-814 can be configured to monitorpatients. For example, the one or more patient care devices 808-814 canbe configured to monitor an oxygen level, a heartrate, a heartbeatpattern, a temperature, a respiration rate, a blood pressure, or thelike.

The master user device 804 can be configured to provide the timing forthe ultra-wide band network 802. Patient medical data collected at thepatient care devices 808-814 can be transmitted, by the patient caredevices 808-814, to an appropriate master user device 804 or slave userdevice 806.

FIG. 8 shows two patient care devices 808 and 812 in wirelesscommunication with master user device 804. Also shown are two patientcare devices 810 and 814 in wireless communication with a slave userdevice 806. All elements, the master user device 804, the slave userdevice 806 and the patient care devices 808-814 are all operating withinthe same ultra-wide band network 802. Interference between these devicescan vary significantly. Variations in the interference can be caused bydifferent distances between the different ultra-wide band networkelements, localized interference caused by one or more of the ultra-wideband network elements, localized environmental conditions, third-partyelements, or the like.

In some variations, one or more of the ultra-wideband network elementscan be configured to receive a signal from another one of the one ormore ultra-wideband network elements. The one or more ultra-widebandnetwork elements can be configured to determine a received signalstrength indication (RSSI) measurement for the signal received fromanother one of the one or more ultra-wideband network elements. Thereceived signal strength indication measurement can provide anestimation of the input received signal level for proper control of theautomatic gain control (AGC) circuitry that a network element needs toapply in order to prevent limiting in the receiver front-endamplification and the analog-to-digital conversion (ADC) process. RSSIis the measure of a relative quality of a received signal to the networkelement. It is the measurement of power present in the received signal.RSSI output can be, for example, a DC analog level. The RSSI can besampled by an internal ADC.

In some variations, the one or more ultra-wideband network elements canbe configured to determine a received channel power indicator (RCPI).RCPI can be a measure of the received radio frequency power in aselected channel over the preamble to a data packet and the entirereceived frame of the data packet. In some examples, RCPI can be definedabsolute levels of accuracy and resolution with which to compareagainst.

The received signal strength indicator (RSSI) measurement can provide anestimation of the received signal strength over the wide bandwidth ofthe UWB signal. The estimation of the received signal strength caninclude the summation of the desired signal, noise, interference, andthe like. In some variations, one or more of the ultra-wideband networkelements can be configured to modify the preamble of a data packet. Forexample, an initial estimation of the desired signal strength can beprovided in the preamble of a UWB data packet. Depending on the burstdata rate used for the data transmission and the packet burst mode, thepreamble can, for example, consist of 30 symbols for the standardpreamble and 18 symbols for the burst preamble. The standard and burstpreamble can contain a Packet/Frame synchronization sequence and channelestimation symbols. The Packet/Frame synchronization sequence canprovide the wideband estimation. The channel estimation can provide anarrowband observation across the entire UWB bandwidth. Packet/Framesynchronization at an ultra-wideband network element can cause theultra-wideband network element to perform signal processing in the timedomain using a correlation algorithm. Channel estimation processing inthe frequency domain can use a Fast Fourier Transform (FFT) algorithmfor each channel symbol. In some variations, the correlation algorithmcan use a known time domain sequence. The channel frequency estimationalgorithm can use a known frequency domain response.

In some examples, the Packet/Frame synchronization sequence of thepreamble can make up the first 24 symbols of the standard preamble andfirst 18 symbols of the burst preamble. Each symbol of the Packet/Framesynchronization sequence (for example, 312.5 ns) can consist of a 128sample time frequency code (TFC) followed by 37 samples of zeros at asample rate of 528 Msps (Mega samples per second). Time frequency codescan define the single channel frequency operation or the channelfrequency hopping for utilizing multiple bands within a band group asdefined in Table 2.

FIG. 9 shows a graph 900 illustrating the sequence 902 for TFC 6,providing a 128 sample code from sample 0 to 127, followed by 37 zerosfrom sample 128 to 164 (denoted as sequence 904); at sample 165 (denotedat 906) the same sequence 902 followed by sequence 904 repeats.Processing of the Packet/Frame synchronization sequence can providepacket acquisition and detection, coarse carrier frequency estimation,coarse symbol timing, and synchronization within the preamble.Correlation detection of the TFCs can provide the information used foracquisition, detection, estimation, and the like, of the synchronizationparameters.

FIG. 10 shows a graph 1000 illustrating the sliding correlation outputversus time samples for the first and second TFC 6 sequence. The firstcorrelation peak 1002 occurs at sample 128, while the second correlationpeak 1004 occurs at sample 293, which corresponds to 165 samples betweencorrelation peaks as expected (128 sample TFC plus 37 zero samplesequals 165 samples). As shown in FIG. 10 cross correlation results canexist between the correlation peaks as the transmit TFC slides acrossthe TFC correlation reference. Cross correlation magnitude values, shownin FIG. 3, are less than 20, with 88.7% of the cross correlationmagnitude values less than or equal to 6 and 93.2% less than or equal to9. Over these cross-correlation magnitude areas of the correlationsignal, an estimation of the noise and interference level can be made,while the correlation peaks can be used to make a wideband estimation ofthe signal.

For the preamble described above, there are 24 TFC sequencestransmitted. The burst preamble, described above, can transmit 12 TFCsequences. The correlation peaks generated by the reception of themultiple TFC sequences can provide the information to estimate thecoarse carrier frequency estimation and coarse symbol timing within thepreamble. These multiple correlation peaks can also be combined forenhanced wideband estimation. This is particularly the case at the lowerreceived signal levels. In some examples, the impact of the carrierfrequency error can be accounted for in the combining of the correlationpeaks. When using the ECMA-368 standard, that sets the maximum frequencyerror requirement equal to ±20 ppm at both the transmitter and receiver,the carrier phase will change across the correlation of the multipleTFCs.

Table 6 gives the maximum carrier phase error introduced between twocorrelation peaks for the different UWB band groups. As the operationalcarrier frequency increases, the phase error between correlation peaksalso increases. For operation in band groups 3 to 6, the maximum phaseerror goes from approximately 30 to 46 degrees.

TABLE 6 Carrier Phase Error across TFC Sequence Correlations UWB UWBChannel Frequencies (MHz) Max Frequency Error (kHz) Max Phase Band BandCenter Lower Upper Center Lower Upper Error Group Number Freq Freq FreqFreq Freq Freq (Deg) 1 1 3432 3168 3696 137.28 126.72 147.84 15.44 23960 3696 4224 158.4 147.84 168.96 17.82 3 4488 4224 4752 179.52 168.96190.08 20.20 2 4 5016 4752 5280 200.64 190.08 211.2 22.57 5 5544 52805808 221.76 211.2 232.32 24.95 6 6072 5808 6336 242.88 232.32 253.4427.32 3 7 6600 6336 6864 264 253.44 274.56 29.70 8 7128 6864 7392 285.12274.56 295.68 32.08 6 9 7656 7392 7920 306.24 295.68 316.8 34.45 4 108184 7920 8448 327.36 316.8 337.92 36.83 11 8712 8448 8976 348.48 337.92359.04 39.20 12 9240 8976 9504 369.6 359.04 380.16 41.58 5 13 9768 950410032 390.72 380.16 401.28 43.96 14 10296 10032 10560 411.84 401.28422.4 46.33

Two approaches for combining the correlation peaks can includenon-coherent or coherent combining. Non-coherent combining can generatethe magnitude of the correlation peaks by summing the squared inphaseand squared quadrature correlation peaks to remove the carrier phaseerror.

The more complicated coherent combining approach requires the estimationof the carrier frequency error from the correlation peaks, provided bythe shape of the correlation peaks, and using the carrier frequencyerror to remove the carrier phase drift from the correlation peaks.Besides, introducing additional latency to perform all the carrier phasedrift processing, coherent combining, compared to non-coherentcombining, will require hardware to estimate the carrier phase drift andgenerate the cosine and sine signals required to remove the carrierphase drift between the correlation peaks. The non-coherent combiningcan provide a faster approach with the lowest hardware complexity andpower consumption.

When estimating the signal strength, in addition to carrier frequencydrift, the time spread of the correlation peak introduced by signalfiltering in the transmitter and receiver can also be taken into accountwhen estimating the signal strength.

FIG. 11 illustrates a graph 1100 showing an example of the time spreadof the correlation peak introduced by transmit and received filtering,using operations having one or more features consistent with thepresently described subject matter. The time spread of the correlationpeak introduced by transmit and received filtering are the practicaleffects of bandwidth limitation. The single correlation peak (1002 or1004) shown in FIG. 10 now spreads across ±6 samples from thecorrelation peak. In addition, the correlation response shape changeswith respect to the sample timing between the transmitter and receiverclock reference. Timing offset of a half of a sampling period can resultin the maximum timing offset condition. Graph 1100 shows the differentcorrelation response shapes for on time 1102 and maximum timing offset1104 conditions. For maximum timing offset 1104, the correlation shapechanges significantly with two peak values resulting. The correlationresponse shape can be used for coarse time synchronization. For signalestimation, three to four samples about the correlation peak can be usedin the estimation. The correlation samples ±6 from the correlation peakwill be excluded from correlation samples used in the wideband noise andinterference estimate.

In some variations, 6 symbols used for channel estimation can follow thePacket/Frame synchronization sequence of the preamble. For each of the 6symbols, a specified Quadrature Phase Shift Keyed (QPSK) modulationphase can modulate each of the FFT subcarriers, except for the six (6)null subcarriers.

Table 7 gives the Quadrature Phase Shift Keyed (QPSK) real and imaginarycomponents that determine the QPSK phase for each of the subcarriers. Inaddition, Table 7 provides the subcarrier definition within a datasection of a packet. Besides providing a channel estimation, theresponse across the received subcarriers can be used to provide both awideband and narrowband estimation of received signal power. Subcarriersignal power across the bandwidth can be compared against the individualsubcarriers to identify areas of the bandwidth with high interferencelevels. Measured high interference levels can be compared against theinterference measurements from the correlation process.

TABLE 7 Channel Estimation Subcarrier QPSK Modulation Symmetric FFTChannel Estimation FFT Subcarrier Subcarrier FFT Components SubcarrierIndex Index Real Imag Phase Type −63 65 0 0 Null −62 66 0 0 Null −61 67−1 1 135 Guard −60 68 −1 1 135 Guard −59 69 −1 1 135 Guard −58 70 −1 1135 Guard −57 71 −1 1 135 Guard −56 72 1 −1 −45 Data −55 73 1 −1 −45Pilot −54 74 −1 1 135 Data −53 75 1 −1 −45 Data −52 76 1 −1 −45 Data −5177 1 −1 −45 Data −50 78 1 −1 −45 Data −49 79 1 −1 −45 Data −48 80 −1 1135 Data −47 81 1 −1 −45 Data −46 82 −1 1 135 Data −45 83 −1 1 135 Pilot−44 84 1 −1 −45 Data −43 85 1 −1 −45 Data −42 86 −1 1 135 Data −41 87 −11 135 Data −40 88 1 −1 −45 Data −39 89 1 −1 −45 Data −38 90 1 −1 −45Data −37 91 −1 1 135 Data −36 92 1 −1 −45 Data −35 93 −1 1 135 Pilot −3494 −1 1 135 Data −33 95 1 −1 −45 Data −32 96 1 −1 −45 Data −31 97 1 −1−45 Data −30 98 1 −1 −45 Data −29 99 −1 1 135 Data −28 100 −1 1 135 Data−27 101 1 −1 −45 Data −26 102 1 −1 −45 Data −25 103 1 −1 −45 Pilot −24104 −1 1 135 Data −23 105 1 −1 −45 Data −22 106 1 −1 −45 Data −21 107 1−1 −45 Data −20 108 −1 1 135 Data −19 109 1 −1 −45 Data −18 110 1 1 135Data −17 111 1 −1 −45 Data −16 112 1 −1 −45 Data −15 113 −1 1 135 Pilot−14 114 −1 1 135 Data −13 115 −1 1 135 Data −12 116 1 −1 −45 Data −11117 1 −1 −45 Data −10 118 −1 1 135 Data −9 119 1 −1 −45 Data −8 120 −1 1135 Data −7 121 1 −1 −45 Data −6 122 −1 1 135 Data −5 123 −1 1 135 Pilot−4 124 1 −1 −45 Data −3 125 −1 1 135 Data −2 126 1 −1 −45 Data −1 127 1−1 −45 Data 0 0 0 0 Null 1 1 1 1 45 Data 2 2 1 1 45 Data 3 3 −1 −1 −135Data 4 4 1 1 45 Data 5 5 −1 −1 −135 Pilot 6 6 −1 −1 −135 Data 7 7 1 1 45Data 8 8 −1 −1 −135 Data 9 9 1 1 45 Data 10 10 −1 −1 −135 Data 11 11 1 145 Data 12 12 1 1 45 Data 13 13 −1 −1 −135 Data 14 14 −1 −1 −135 Data 1515 −1 −1 −135 Pilot 16 16 1 1 45 Data 17 17 1 1 45 Data 18 18 −1 −1 −135Data 19 19 1 1 45 Data 20 20 −1 −1 −135 Data 21 21 1 1 45 Data 22 22 1 145 Data 23 23 1 1 45 Data 24 24 −1 −1 −135 Data 25 25 1 1 45 Pilot 26 261 1 45 Data 27 27 1 1 45 Data 28 28 −1 −1 −135 Data 29 29 −1 −1 −135Data 30 30 1 1 45 Data 31 31 1 1 45 Data 32 32 1 1 45 Data 33 33 1 1 45Data 34 34 −1 −1 −135 Data 35 35 −1 −1 −135 Pilot 36 36 1 1 45 Data 3737 −1 −1 −135 Data 38 38 1 1 45 Data 39 39 1 1 45 Data 40 40 1 1 45 Data41 41 −1 −1 −135 Data 42 42 −1 −1 −135 Data 43 43 1 1 45 Data 44 44 1 145 Data 45 45 −1 −1 −135 Pilot 46 46 −1 −1 −135 Data 47 47 1 1 45 Data48 48 −1 −1 −135 Data 49 49 1 1 45 Data 50 50 1 1 45 Data 51 51 1 1 45Data 52 52 1 1 45 Data 53 53 1 1 45 Data 54 54 −1 −1 −135 Data 55 55 1 145 Pilot 56 56 1 1 45 Data 57 57 −1 −1 −135 Guard 58 58 −1 −1 −135 Guard59 59 −1 −1 −135 Guard 60 60 −1 −1 −135 Guard 61 61 −1 −1 −135 Guard 6262 0 0 Null 63 63 0 0 Null 64 64 0 0 Null

In some examples, twelve symbols containing the packet header can followthe data packet preamble. The twelve symbols that contain the packetheader can also use the orthogonal frequency-divisional multiplexed(OFDM) signal for communications. Packet header subcarriers can be QPSKmodulated using the same one hundred data subcarriers, twelve pilotsubcarriers and ten guard band subcarriers with six null subcarriers(refer to Table 7 for FFT subcarrier type) as used for the data symbols.Individual subcarrier power levels can provide a narrowband receivedsignal estimation, while the average subcarrier signal power level andvariation across the FFT subcarriers can provide a wideband receivedpower estimate. These narrowband and wideband estimations can becompared against previous estimations to determine if interferencelevels within the communications channels have changed.

For data symbols, the data subcarriers can be modulated by either QPSKor Dual-Carrier Modulation (DCM). DCM is a form of 16 QuadratureAmplitude Modulation (QAM) that introduces amplitude modulation into thedata subcarrier. This can result in a signal power difference of 9.54 dBbetween the minimum and maximum signal power. Average DCM datasubcarrier signal power, for all the 16 different data conditions,delivers the same signal power as that obtained for the QPSK modulateddata subcarriers. For burst data rates operating in the 53 to 200 Mbpsrange, data subcarriers can be modulated using QPSK. Data subcarrierscan be modulated with DCM for burst data rates operating in the 320 to480 Mbps range. In some examples, to account for the signal powerdifference introduced by DCM, the detected four data bits for the datasubcarrier can be used to provide the appropriate power weighting tonormalize the subcarrier power to the same level. This requiresadditional processing of the data subcarrier power measurements. Tominimize data subcarrier power processing for DCM, the 12 pilotsubcarriers which are QPSK modulated can be used for a coarserestimation of the signal power using the same algorithm as used for QPSKdata modulation, except with fewer subcarrier measurements. Since DCMdoes not provide the robust communications against interference, thiscomparatively simplified pilot subcarrier approach can deliver anadequate estimate without adding significant complexity, powerconsumption and processing requirements to the system.

The minimum, maximum and average wideband and narrowband subcarriersignal estimation over the entire data packet can be determined byprocessing the estimations determined over each symbol. Following thedata subcarrier signal power estimations, the corrected Viterbi encodedsymbol errors in the data communications reception processes can beaccumulated to be compared with the measured wideband and narrowbandsignal levels in estimating the signal and interference levels. Alongwith the Viterbi symbol correction, the Frame Check Sequence results(Pass/Fail & number of errors) for the packet can be obtained. Inaddition, the wideband interference plus noise measurement from thecorrelation process can be made available.

FIG. 12 is a process diagram illustrating a method 1200 that includesone or more aspects of the present description. Method 1200 is directedto a receiver wideband and narrowband estimation algorithm process. Oneor more operations of the method 1200 can be performed by one or moreultra-wideband network elements. For example, the one or more operationsof the method 1200 can be performed by each of the ultra-widebandnetwork elements illustrated in FIG. 8, including the user device 804(functioning as the master node), the user device 806 (functioning as aslave node), and the patient care devices 808-814.

At 1202, the one or more network elements can be configured to searchfor a signal. The operations conducted at 1202 can be performed by areceiver of the one or more network elements. The receiver can be astandalone receiver and/or part of a transceiver. In some variations,the one or more network elements may comprise multiple receiversconfigured to detect signals having different signal powers andoperating at different carrier frequencies.

At 1204, automatic gain control circuitry can be used to preventlimiting in the receiver front-end amplification and analog-to-digitalconversion process. The operations at 1204 can be performed by one ormore hardware elements within the one or more network elements. Theoperations at 1204 can provide a received signal strength indicator(RSSI) measurement that can be used as an estimation of the receivedsignal strength over the wide bandwidth of the ultra-wideband (UWB)signal.

At 1206, the packet/frame synchronization sequence can be read by one ormore hardware elements of the one or more hardware elements. At 1208, anestimate of the signal level can be determined based on the correlationvalues from the packet/frame synchronization sequence. At 1210, anestimate of interference plus noise level can be determined based on thecross-correlation values. The cross-correlation values can be determinedby one or more functions as described in the present disclosure.

At 1212, the wideband estimations of automatic gain control, signal andnoise plus interference can be stored. The wideband estimations can bestored in memory. The memory can be part of the one or more networkelements.

At 1214, in response to no synchronization correlation being present,the process can restart at operation 1202 and the stored widebandestimations can be purged from memory. At 1214, in response tosynchronization being detected, the stored wideband estimations can bemaintained in memory.

At 1216, in response to detection of synchronization correlation,wideband and narrowband subcarrier signal levels can be collected. Thewideband and narrowband subcarrier signal levels can be determined basedon the channel estimation systems. Similarly, at 1218, wideband andnarrowband subcarrier signal levels can be collected that are based onthe MB-OFDM symbol FFT processing.

At 1220, wideband signal levels can be estimated based on the subcarrierlevels collected by the operations described at 1216. At 1222,narrowband signal levels can be estimated based on the subcarrier levelscollected by the operations described at 1216.

At 1224, the wideband signal levels estimated at 1220 can be comparedwith the wideband signal level estimations stored in memory at 1212. At1225, the comparison of the wideband signal level estimations can bestored.

At 1226, the narrowband signal levels estimated at 1222 can be stored inmemory.

At 1228, the narrowband signal levels can be estimated based on thesubcarrier levels collected at 1218. At 1230, the wideband signal levelscan be estimated based on the wideband signal levels obtained at 1218.The signal levels estimated at 1228 and 1230 being based on the MB-OFDMsymbol FFT processing that occurs at 1218.

At 1232, narrowband levels estimated at 1226 and 1228 can be compared.At 1234, the comparison of the narrowband results can be stored inmemory for comparison against narrowband levels of following OFDMsymbols in the transmission. At 1236, wideband levels estimated at 1230can be compared with the stored results at 1225. At 1238, the widebandresults of the comparison at 1236 can be stored in memory for comparisonagainst wideband levels of following OFDM symbols in the transmission.

FIG. 13 is a process diagram illustrating a method 1300 that includesone or more aspects of the present description. Method 1300 is directedto one or more aspects additional to the method 1200 illustrated in FIG.12. One or more operations of the method 1200 can be performed by one ormore ultra-wideband network elements. For example, the one or moreoperations of the method 1300 can be performed by each of theultra-wideband network elements illustrated in FIG. 8, including theuser device 804 (functioning as the master node), the user device 806(functioning as a slave node), and the patient care devices 808-814.

At 1302, symbol processing can be continued. For example, the symbolprocessing can be continued from 1218 illustrated in FIG. 12. At 1304,the results from the symbol processing can be stored in memory. Thememory can be an electronic memory of the one or more ultra-wide bandnetwork elements. The results for wideband results and the results fornarrowband results can be stored separately. Separate storage, as usedherein, can refer to storing results in different files, differenttables of a database, different data objects, in different portions of adata object or the like. In some variations, the narrowband and widebandresults can be stored in different electronic memory components. Forexample, at 1306, wideband results can be stored for comparison with thewideband results previously stored in memory, such as at operation 1238.At 1308, narrowband results can be stored for comparison with thenarrowband results previously stored in memory, such as at operation1234.

At 1310, wideband and narrowband subcarrier signal levels can becollected. The wideband and narrowband subcarrier signal levels can bebased on MB-OFDM symbol FFT processing. In some examples, the widebandand narrowband subcarrier signal levels collected at 1310 can be of adifferent OFDM symbol within the transmission than the wideband andnarrowband subcarrier signal levels collected at 1218.

At 1312, the narrowband signal levels can be estimated. The estimationof the narrowband signal levels can be based on the subcarrier levels.At 1314, the estimated narrowband signal levels can be compared with thenarrowband results stored into memory at 1308 and/or 1234. At 1316, theresults from the comparison at 1314 can be stored into memory. In someexamples, storing the results into memory, at 1308 and/or 1316 caninclude updating the results already stored in memory.

At 1318, the wideband signal levels can be estimated for an OFDM symbol.The estimation of the wideband signal levels can be based on subcarrierlevels within the OFDM symbol. At 1320, the wideband signal levelsestimated at 1318 can be compared with the wideband signal levels storedin memory at 1306 and 1238. At 1322, the results of the comparison canbe stored into memory. In some examples, storing the results into memorycan include updating the results already stored in memory.

At 1324, a determination can be made as to whether 6 symbols have beenprocessed. In response to a determination that 6 symbols have not beenprocessed the operations at 1302 can be repeated. In response to adetermination that 6 symbols have been processed the operations at 1326can proceed. The processing of 6 symbols is exemplary. Other numbers ofsymbols can be processed based on the waveform structure, such as the 6symbol interleaver depth used in this example. Some packet systems mayhave varying numbers of symbols, after the packet/frame preamble, thatare used for channel estimation.

At 1326, signals can be de-interleaved over 6 OFDM symbols based on thetransmitter interleaving depth of 6 OFDM symbols and the Viterbi symbolscan be decoded.

At 1328, a measurement of the number of corrected Viterbi symbols can betaken. At 1330, the measurement of the number of corrected Viterbisymbols can be accumulated over a number of iterations of the processrepresented by the methods 1200 and 1300. At 1332, the corrected symbolmeasurements can be stored in memory.

At 1334, a determination can be made as to whether all of the OFDMsymbols have been processed. In response to a determination that not allof the OFDM symbols have been processed, the operations at 1302 can berepeated. At 1336, in response to a determination that all of the OFDMsymbols have been processed a frame check sequence can be processed.

FIG. 14 is a process diagram illustrating a method 1400 that includesone or more aspects of the present description. Method 1400 is directedto a master node UWB network interference algorithm.

At 1402, interference information measured at one or more networkelements using one or more elements of methods 1200 and/or 1300, can bereceived at a master node. For example, interference informationmeasured by one or more network elements 806-814, illustrated in FIG. 8,can be transmitted to the master node, such as user device 804,illustrated in FIG. 8.

At 1404, a measurement of the wideband signal and interference plusnoise levels can be made. The measurement of the wideband signal and theinterference plus noise levels can be measured using the correlationprocess described herein. The measurement of the wideband signal andinterference plus noise level can be based on the wideband signal andinterference plus noise level measured at a particular slave node of theultra-wideband network. The measurement of the wideband signal andinterference plus noise levels can be performed by the master node. At1406, the results of the measurement of the wideband signal andinterference plus noise levels using the correlation process can bestored in memory of the master node.

At 1408, a measurement of the wideband and narrowband signal levelsusing FFT subcarriers can be made. The measurement of the wideband andnarrowband signal levels using FFT subcarriers can be based on aparticular slave node of the ultra-wideband network. Measurement of thewideband and narrowband signal levels using FFT subcarriers can beperformed by the master node. At 1410, the results of the measurement ofthe wideband and narrowband signal levels using FFT subcarriers can bestored in memory.

At 1412, a count of the Viterbi symbol corrections can be performed. Thecount can be based on a particular slave node of the ultra-widebandnetwork. The count can be performed by the master node. At 1414, theresults of the count can be stored in memory of the master node.

At 1416, a Frame Check Sequence (FCS) can be performed. The FCS can bebased on a particular slave node. The FCS can be performed by the masternode. At 1418, the results of the FCS can be stored in memory of themaster node.

At 1420, the wideband and narrowband signal estimations from each nodeof the ultra-wideband network can be stored in memory.

At 1422, the wideband and narrowband signal estimations stored at 1420can be compared with the results stored at 1406, 1410, 1414, and 1418.

At 1424, the wideband and narrowband signal estimations from eachnetwork element of the ultra-wideband network can be compared. Forexample, the wideband and narrowband signal estimations from the userdevices 804 and 806, and the patient care devices, 808-814, illustratedin FIG. 8 can be compared by the user device 804.

At 1426 a determination can be made as to whether to change theultra-wideband channel used for communication by the network elements inthe ultra-wide band network. In response to determining at 1426 that nochange of the channel is required, the process starting at 1402 can berepeated.

At 1428, in response to determining, at 1426, that a change in theultra-wideband channel is required, a channel scan can be performed bythe master node. An instruction to change the channel can be sent by themaster node to each slave node.

At 1430, in response to an acknowledgement, received at the master nodeand from the slave nodes of the ultra-wideband network, the channel usedfor communication by the network elements of the ultra-wideband networkcan be changed based on the channel scan.

FIGS. 12-14 show Viterbi symbol correction and Frame Check Sequence(FCS) information being used to estimate the signal and interferencelevels in the communications channel. This information can be collectedat the patient care devices CAMIT modules, such as patient care devices808, 810, 812 and 814 illustrated in FIG. 8 and one or more slave userdevice CAMIT modules, such as user module 806 illustrated in FIG. 8. Theinformation can be sent back to the master user device CAMIT modulenode, for example, user device 804 illustrated in FIG. 8. The masteruser device CAMIT module can be configured to estimate the signal andinterference levels across the ultra-wide band network, based on thereceived information, and determine if a change in the ultra-widebandnetwork channel should be made.

The master node, such as user device 804 illustrated in FIG. 8, can usethe received signal and interference levels received from each of theconnected nodes combined with the received signal and interferencelevels collected at the master node, from the signal reception from eachnode, to estimate the interference level at each node within theultra-wideband network, such as ultra-wideband network 802 illustratedin FIG. 8. The master node can process this signal and interference dataand determine if the operational channel needs to be changed. If themaster node decides on using a different channel, the master node can beconfigured to scan the list of available channels followed by a messageto the connected nodes within the ultra-wideband network instructingthem to change to the new channel. For example, with reference to FIG.8, user device 804 can be configured to send an instruction to the otherultra-wideband network elements to change a channel. Patient caredevices 808 and 812 and user device 806 may have a direct connectionwith the user device 804. Patient care devices 810 and 814 may directlyconnect to the user device 806, which is a slave node to the master nodethat is use device 804. User device 806 can be configured to relay theinstruction to change channel to the patient care devices 810 and 814.The connected nodes will, in turn, acknowledge this channel changebefore moving to the selected channel. For example, patient care devices808 and 812 and user device 806 can directly communicate acknowledgementthe change. User device 806 can be configured to relay, to the userdevice 804, the acknowledgement from patient care devices 810 and 814.

During channel scan, the master node, such as user device 804, can useprevious channel information in the scanning algorithm. This can resultin channels that have previously been found with significantinterference being moved to the bottom of the scan list. In this manner,the master node does not waste time trying to determine whether there isinterference on a channel that has previously been known to havesignificant interference.

One non-limiting exemplary advantage of the presently described subjectmatter can include improved estimation of interference to communicationsover a channel in a UWB network.

FIG. 15 shows a process flow of a method 1500 having one or morefeatures consistent with the presently described subject matter. One ormore operations described with respect to method 1500 can be performedby one or more of the network elements described with respect to FIG. 8.

At 1502, a wideband signal can be received. The wideband signal can bereceived by a first set of slave nodes. In some variations, the firstset of slave nodes can comprise one or more slave nodes. The first setof slave nodes can be at least a first part of a wideband network. Thewideband network can use a wideband channel for communicating betweennetwork elements of the wideband network.

In some variations, the first set of slave nodes comprise a patient caredevice. The master node can comprise a user device. For example, patientcare devices 808-814 illustrated in FIG. 8 and user devices 804 and 806illustrated in FIG. 8.

In some variations, the wideband signal received at the first set ofslave nodes can comprise a signal burst preamble.

At 1504, signal strength of the received wideband signal can bemeasured. The signal strength of the received wideband signals can bemeasured by the first set of slave nodes. The measurement of the signalstrength of the received wideband signals can include signal processing,using one or more of the signal processing techniques described herein.

At 1506, a noise level can be determined for the received widebandsignal. The noise level can be determined by the first set of slavenodes. The noise level can be determined using one or more signalprocessing techniques described herein. In some examples, thedetermining of the noise level can be based on a number of symbolcorrections required for the received wideband signal.

At 1508, a first estimated amount of interference, of the receivedwideband signal can be estimated. The first estimated amount ofinterference can be estimated by the first set of network nodes.

At 1510, the first estimated amount of interference can be transmittedfrom the first set of slave nodes and to a master node.

At 1512, an estimated amount of network interference can be generated.The estimated amount of network interference can be generated bycomparing the first estimated amount of interference with a secondestimated amount of interference from a second set of slave nodes. Thesecond set of slave nodes can be at least a second part of a widebandnetwork. The estimated amount of network interference can be generatedby the master node.

In some variations, the method 1500 can comprise estimating theinterference level at the master node. The master node estimates theamount of interference at the master node using the received signal fromthe slave nodes. The master node estimates amount of interference at themaster node by comparing the received signal strength from the slavenodes versus the transmitted signal level by the slave nodes. Inaddition, the master node can measure signal strength during nonereception intervals for an estimation of the node noise level at themaster node.

The generated estimated amount of network interference can be furtherbased on the estimated amount of interference of the master nodewideband signal.

FIG. 16 shows a process flow of a method 1600 having one or morefeatures consistent with the presently described subject matter. One ormore operations described with respect to method 1600 can be performedby one or more of the network elements described with respect to FIG. 8.The method 1600 can include one or more operations that are supplementalto the operations described for method 1500.

At 1602, another channel (new channel selection) for the widebandnetwork can be selected. The new channel can be used by the one or morenetwork elements to communicate with each other. The new channel can beselected by the master node. The new channel can be selected in responseto the estimated amount of network interference on the channel exceedinga threshold interference value.

At 1604, an instruction to move to another channel (new channelselection) can be transmitted. The instruction can be transmitted fromthe master node and to the first set of slave nodes and the second setof slave nodes.

At 1606, an acknowledgement from the first set of slave nodes of receiptof the instruction can be received. The acknowledgement can be receivedat the master node and from the first set of slave nodes and the secondset of slave nodes.

At 1608, communications can be moved from the present operating channelto the new selected channel. The communications can be moved from thepresent operating channel to the new selected channel in response to thereceipt of the acknowledgement from the first set of slave nodes and thesecond set of slave nodes.

In one aspect, a burst rate can be selected for a wireless network thatis less than the maximum possible burst rate for the wireless network.The wireless network can be an ultra-wideband network. In some examples,the wireless network can facilitate communication between a Patient CareDevice (PCD) to a medic's User Device (UD). The PCD can be configured tomonitor one or more physical characteristics of a patient associatedwith the PCD. One or more Close Area Medical Integration Technology(CAMIT) modules can be configured to use the Ultra-Wideband (UWB)Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) togetherwith a selection of a reduced burst data rate, compared to the maximumpossible data rate between the CAMIT modules, for communications. Thereduced burst rate can be determined using one or more burst rateselection algorithms, as described herein.

Some exemplary use cases for the presently described burst rateselection for wireless communications, is the transmission of medicaldata. To provide a robust secure wireless transmission of medical datafrom a Patient Care Device (PCD) monitoring one or more characteristicsof a patient, for example, a patient's vitals, to a medic's User Device(UD), the Close Area Medical Integration Technology (CAMIT) modulesusing the Ultra-Wideband (UWB) Multi-Band Orthogonal Frequency DivisionMultiplexing (MB-OFDM) can be configured to use a reduced burst datarate selection for communications and a different selection algorithm toselect the reduced burst data rate.

TABLE 8 UWB Burst Data Rates Redundant Burst Coded bits Info Data CodeCoding Data Rate per 6 bits per Modulation Rate TDS FDS (Mbps) ModSymbol Symbol QPSK 1/3 2 2 53.33 300 100 QPSK 1/2 2 2 80.00 300 150 QPSK1/3 2 1 106.67 600 200 QPSK 1/2 2 1 160.00 600 300 QPSK 5/8 2 1 200.00600 375 DCM 1/2 1 1 320.00 1200 600 DCM 5/8 1 1 400.00 1200 750 DCM 3/41 1 480.00 1200 900

Table 8 shows an example of eight different data rates that areavailable with the MB-OFDM ultra-wideband waveform with Quadrature PhaseShift Keying (QPSK) modulation being used for the lowest five data burstrates. The five lowest QPSK burst data rates, shown in Table 8, canprovide the five different burst data rates by changing a Forward ErrorCode (FEC) rate (for example, by ⅓, ½, ⅝, or the like), the Time DomainSpreading (TDS) parameters, the Frequency Domain Spreading (FDS)parameters, or the like.

TABLE 9 ECMA-368 Receiver Sensitivity Burst Data Receiver Sensitivity(dBm) Rate (Mbps) from ECMA-368 Standard 53.33 −80.8 80.00 −78.9 106.67−77.8 160.00 −75.9 200.00 −74.5 320.00 −72.8 400.00 −71.5 480.00 −70.4

Table 9 provides the ultra-wideband receiver sensitivity requirementsgiven in the ECMA-368 standard. As shown Table 9, the five lowest datarates can provide a 6 dB change in receiver sensitivity forapproximately a 3.7 times change in data burst rate. The lower receiversensitivity offered by the 53.33 Mbps burst rate provides a 6 dB lowerreceiver sensitivity, which can be used to overcome path loss variationsintroduced by the spatial movement of the user device (UD) with respectto the patient care devices (PCD). This lower data burst rate canrequire more transmission time to communicate the medical informationcompared to higher data burst rates. However, the lower receiversensitivity level can provide a higher reliability of the signal beingreceived at the user device from the patient care device. This isespecially true when the user device is spatially moving relative to thepatient care device. By increasing the reliability of a signal beingsuccessfully received at the user device, the number of retransmissionsof the same critical medical data can be reduced. Operation at the lowerburst data rates can increase the reliability of the communications.Increasing the reliability of the communications can have a net positiveimpact by providing increased reliability on the data being received atthe medic's user device as well as reducing the frequency at whichretransmissions have to occur.

The presently described subject matter comprises at least two changes tothe burst data rate selection from the ultra-wideband standardimplementation. For example, the presently described algorithm canreduce the burst data rate selection from the lowest burst data rate tohigher burst data rates associated with QPSK modulation. In somevariations, the presently described algorithm can reduce the burst datarate selection from the lowest burst data rate to higher burst datarates associated with QPSK modulation only. The selected burst data ratecan be significantly reduced from the 5 maximum to 2 or even 1 burstdata rate, based on the system operational environment.

As another example, the user device (UD) that is configured to performthe network coordination, for example, the master node, can beconfigured to start communication with patient care devices (PCDs) atthe lowest available burst data rate for the ultra-wideband networkparameters used. This can be an alternative method to selecting theburst data rate which may use collected channel information to selectthe burst data rate and selects the burst data rate by first selecting ahigher burst data rate and moving down to a lower burst data rate. Bystarting at the lowest burst data rate, the communications link can beconfigured to support the highest communications path loss capability.Communications path loss can be influenced by spatial movement of theuser device (UD) and blockage by objects within the communication pathbetween the user device (UD) and the patient care devices (PCDs).

In some variations, channel information and communications performanceat the patient care device and the user device, can be estimated.Estimated channel information and communications performance can be usedto determine if the burst data rate can be increased to a higher burstdata rate.

FIG. 17 is a process flow diagram illustrating aspects of a method 1700having one or more features consistent with implementations of thecurrent subject matter. The method 1700 can be for selection of a burstdata rate. The method 1700 can be illustrative of a burst data ratecontrol algorithm. A burst data rate control algorithm can be configuredto slowly increase the burst data rate being used between wirelesscommunication devices, based on the collected channel and communicationsperformance information. Degradation in the communications link obtainedfrom this collected information or link failure can cause the wirelesscommunication devices, such as a medic's user device and the patientcare device(s), to return to the lowest burst data rate to maintain thecommunications link between the patient care device(s) and medic's userdevice. If the communication link is not maintained at the lowest burstdata rate, re-establishment of the patient care device(s) and the userdevice link can be addressed. In the re-establishment condition, thepatient care device can find that the user device it was previouslyconnected to is no longer in range, no user device is presently in rangeor that a new user device has entered into the range of the patient caredevice and a new link needs to be established between these two networkelements.

At 1702, a user device (UD) and patient care device (PCD) communicationlink can be established. The UD-PCD communication link can be anultra-wideband communication link. In some variations, the communicationlink can be initiated by a master node, such as a user device that isconfigured to manage the communication network on which the user deviceand the patient care device is communicating over.

At 1704, the user device and/or the patient care device can select thelowest available burst data rate for the communications between the userdevice and the patient care device. In some variations, the selectioncan be made by a master node, such as a user device that is configuredto manage the communication network on which the user device and thepatient care device is communicating over.

At 1706, channel and communications performance information at the userdevice and/or the patient care device can be collected. In somevariations, the collection of data can be done by a master node, such asa user device that is configured to manage the communication network onwhich the user device and the patient care device is communicating over.

At 1708, a determination can be made as to whether the channel,currently being used for communications between the user device and thepatient care device, permits an increase in the burst data rate. In somevariations, the determination can be made by a master node, such as auser device that is configured to manage the communication network onwhich the user device and the patient care device is communicating over.

At 1710, in response to a determination that the channel, currentlybeing used for communications between the user device and the patientcare device, does not permit an increase in the burst data rate, adetermination can be made as to whether there are multiple communicationlink failures. If multiple communication link failures are not aproblem, the lowest available burst data rate can be maintained.

At 1712, in response to there being multiple communication linkfailures, a communication link re-establishment procedure can beinitiated. The re-establishment procedure can be initiated by a masternode, such as a user device. In some variations, the patient care devicecan be configured to initiate the re-establishment procedure. Thepatient care device can be configured to re-establish communicationlinks with the same or a different user device.

At 1714, in response to a determination that the channel, currentlybeing used for communications between the user device and the patientcare device, does permit an increase in the burst data rate, the burstdata rate can be increased to the next highest burst data rate.

At 1716, channel and communications performance information at the userdevice and/or the patient care device can be collected. In somevariations, the collection of data can be done by a master node, such asa user device that is configured to manage the communication network onwhich the user device and the patient care device is communicating over.

At 1718, a determination of whether there is a high communication linkfailure can be made. The determination can be made by the user deviceand/or the patient care device. In response to a determination thatthere is a high communication link failure, the user device and/or thepatient care device can be configured to decrease the burst data ratefor the communication channel to the lowest available data burst rate.

At 1720, in response to a determination that high communication linkfailure is not a problem, a determination can be made as to whether thechannel permits an increase in the burst data rate. In some variations,the determination can be made by a master node, such as a user devicethat is configured to manage the communication network on which the userdevice and the patient care device is communicating over. In response toa determination that the channel can permit an increase in burst datarate, the operations at 1718 can be performed. In response to adetermination that the channel does not permit an increase in burst datarate, the operations at 1716 can be performed.

In some variations, the channel and communications performanceinformation collected at the patient care device and the user device caninclude, at least: (1) Received Signal Strength out of the FFT detectionprocess with the RF Front-End Receiver Gain; (2) Number of ErrorCorrection out of the Error Detection Process; and/or (3) Packet Failuredetermined by the incorrect Frame Check Sequence comparison.

In the examples where the user device sets the burst data rate, channeland communications performance information collected at the patient caredevices can be sent back to the user device for burst data rateselection in the data packet. Since channel conditions can be differentat both ends of the link, burst data rate selection can be configured touse the received channel and communications performance information fromthe patient care device and user device so that a burst data rate isselected that is compatible with both devices. Since the medical datatypically flows from the patient care device to the user device, thereception of the medical data at the user device may have increasedcritically compared to other data transmission paths. Communicationsfrom the user device to the patient care device can typically providescheduling and acknowledging information to the patient care device andtherefore might be less critical than the actual medical datatransmitted by the patient care device.

In some variations, the required data transmission rate for medical datatransmitted from the patient care device to the user device may be lessthan 2.56 kbps. A low burst data rate can provide significant datathroughput to support this data throughput rate. Furthermore, the packetsize for the medical data can be relatively small, for example, in theorder of a 2500 bit (320 byte) data packet, and can be packed into halfa Medium Access Slot (MAS=256 μs).

The more MASs the higher the network through-put. Using up less timeslots in a waveform for a low data rate allows for the time slots to beavailable for higher data rate applications and/or additional low datarate node connections.

FIG. 18 is an illustration of a super frame 1800 having one or morefeatures consistent with the presently described subject matter. FIG. 18shows that a 320 byte data packet with data and waveform overheadrequirements of approximately 66 μs, which is less than half of a MediumAccess Slot (MAS), to transmit. Increasing the number of data packet to700 bytes (5.6 kbits) can still enable the burst to fit into the 128 μstime interval of a half a MAS. This reduction in MAS size, allows moreusers and data capacity, while freeing up more MASs for high datathroughput requirements. Table 10 illustrates packet details for the53.33 Mbps burst rate which is an example of the lowest burst rate in anexample of a channel having one or more features consistent with thepresently described subject matter.

TABLE 10 Packet Details for 53.33 Mbps Burst Data Rate Data Data & 53.33Mbps Packet Details Payload Overhead Data Data Overhead Size PayloadThroughput Payload & Payload (bytes) (bytes) (Mbps) (us) (us) 1 23 1.285.625 18.75 10 32 5.12 5.625 18.75 30 52 11.38 9.375 22.5 80 102 21.8716.875 30 320 342 39.25 52.5 65.625 480 502 42.84 76.875 90 700 72245.38 110.625 123.75 1200 1222 48.38 185.625 198.75 1700 1722 49.74260.625 273.75 2200 2222 50.51 335.625 348.75 2700 2722 51.01 410.625423.75 3200 3222 51.36 485.625 498.75 4075 4097 51.77 616.875 630

FIG. 19 is a process flow showing a method 1900 having one or morefeatures consistent with the presently described subject matter. Theoperations of method 1900 can be performed by one or more of thefeatures described herein.

At 1902, a first burst rate for a channel of a wireless network can beselected. The first burst rate can be selected by a user device and/or apatient care device communicating over the wireless network. The channelof the wireless network can have a maximum burst rate higher than thefirst burst rate. The channel can facilitate communication between afirst device and a second device.

At 1904, performance information associated with the channel can bereceived at the first device and/or the second device.

At 1906, a determination of whether the channel permits a second burstrate higher than the first burst rate can be made. The determination canbe based on the received performance information.

At 1908, the second burst rate for the channel can be selected inresponse to the determining.

At 1910, a failure rate of data transmitted between the first device andthe second device on the channel can be determined. The failure rate canbe determined at the first device and/or the second device.

At 1912, a third burst rate can be selected. The third burst rate can beselected in response to determining that the failure rate is above athreshold failure rate. The third burst rate can be less than the firstburst rate.

One none limiting advantage of the presently described subject matter isthe ability to reduce the radio frequency (RF) transmit power, therebyreducing heat in the patient care devices and the user devices andincreasing battery life.

The operation at the lowest burst data rate for low data rateapplications can enable time and frequency redundancy (providingprocessing gain of 6 dB, for example), combined with Viterbi decodererror correction capability, to reduce the RF transmit power for shortrange communications links. Any added redundancy to the data signal,such as data spreading or additional repeated symbols, can increase theprocessing gain that can be used to reduce the RF transmit power. Thepower control algorithm utilized by the user device(s) and/or patientcare device(s) can be configured to override the burst data control. Theburst data control could increase the burst data rate based on theimproved received signal level for a low data rate application. Byreducing the RF transmit power, power consumption and heat generationwithin the patient care device (PCD) can be reduced, resulting in alonger battery life. In addition, the lower RF transmit power level canimprove the Low Probability of Intercept/Low Probability of Detection(LPI/LPD) performance by driving the signal lower into the noise floor.For communications within a transport vehicle or treatment area, theultra-wideband network can consist of short range communication devices,for example, patient care devices (PCDs) and user devices (UDs). ThePCDs and UDs can be configured to collect and monitor the patent medicaldata supplied by the PCDs. For short range communications operating at alow data rate, the collected channel and communications performanceinformation can be used with a wideband and narrowband signal strengthmeasurement to provide an estimation of the received signal strength. Bycomparing the received signal strength estimation against the minimumoperational signal strength reference for the low burst data rate, forexample, a burst data rate of 53.3 Mbps, with an additional controllablesignal margin parameter (for example, in the range of 2 to 3 dB), therecommended reduction in RF transmit power can be determined.

To mitigate small changes in RF transmit power levels that do notsignificantly reduce power consumption, a power reduction step size of 2dB or greater is recommended. For the existing UWB waveform with maximumprocessing gain of 6 dB, the power reduction algorithm provides a rangeof 2 to 6 dB. Providing additional redundancy to the ultra-wide bandwaveform through added redundant symbols or data spreading, the maximumprocessing gain can be expanded to a range of 20 dB. Beforecommunicating the recommended RF transmit power from the receiver to thetransmitter, the receiver can be configured to check the Viterbi errorcorrection across the data packet to verify the reliability of theexisting communications link. A high number of error corrections canresult in recommending no change in the RF transmit power. At the PCD,the recommended RF transmit power reduction level can be sent as anattachment to the patient medical data. At the UD, the recommended RFtransmit power reduction level can be sent as an attachment to theacknowledgement packet to one or more received data packets.

One non-limiting exemplary advantage of the presently described subjectmatter is to provide wireless communication of data with reduced loss,thereby improving the accuracy of the data being received at a UD andreducing the need to retransmit data.

FIG. 20 is an illustration of a system 2000 having one or more featuresconsistent with the presently described subject matter with the additionof a lower and higher data rate UWB link. The UWB hardware 2004, 2008,2010, 2018, 2020, 2028 and 2034 of the system 2000 consists of achipset, transceiver and antenna section given in FIG. 1 that implementsthe UWB communications link and interface with the respective equipment,such as a patient care device or user device tablet, smartphone orlaptop.

The system 2000 can include one or more patient care devices 2002 thatare connected on the low data rate UWB link to the user device 2006. TheUWB hardware 2004 in the patient care device 2002 communications to theUWB hardware 2008 in the user device 2006 over the lower data rate UWBcommunications link setup by the UWB link processor 2012 in the userdevice 2006. The user device 2006 contains two UWB hardware elementsthat can be configured to provide a low or high data rate UWB link. Forthe specific system configuration 2000 given in FIG. 20, the user deviceUWB hardware 2008 provides connection to the low data rate UWB link andthe user device UWB hardware 2010 provides connection to the high datarate UWB link for supporting video and other higher data rateapplications. The low data rate link provided by the UWB hardware 2008enables the user device 2006 to support low data rate information toanother user device 2016 or/and an access point 2026 connected to aradio 2032 capable of supporting the low data rate information forextended communications range. The high data rate link provided by theUWB hardware 2010 enables the user device 2006 to support video trafficto another user device 2016 or/and an access point 2026 connected to ahigh data rate radio 2038 for extended communications range. Interfacebetween the low data rate UWB hardware 2028 and the radio 2032 used forextended range communications of low data rate transmission is supportby the interface element 2030. Interface between the high data rate UWBhardware 2034 and the radio 2038 used for extended range communicationsof high data rate transmission is support by the interface element 2036.

Received high data rate information can be generated from an externalvideo device that communicates with the user device using theultra-wideband waveform discuss throughout or a cable connection, suchas a universal serial bus (USB) cable or the link. With videocapabilities being built in laptops, tablet, smartphones, and the like,the video capabilities are generated internally at the user device.Internal video generation enables the user to provide added capabilitywithout an added device.

The UWB link processor 2012 collects the measured channel information,data requirements, the number of patient devices connected to the userdevice to determine the allocation of the two UWB hardware elements.Channel information with respect to received signal strength,interference estimation, and burst data rate capability based on theapproaches presently described are used to select the operationalfrequencies for the two UWB link. As shown in system 2000, one UWB linksupports low data rate operation with the other UWB link supports highdata rate operation. FIG. 20 demonstrates a typical configuration wherepatient data from a patient care device 2002 is received at a userdevice 2006 over the low data rate UWB link and the user device 2006uses the high data rate UWB link to transmit patient pictures and/orvideo information to another user device 2016 and/or an access point2026 for transmission over a radio link. The user device 2006 can usethe low data rate to transmit low data rate information to an accesspoint 2026 for extended range communications.

This does not preclude the two UWB links being configured in one of thethree possible configurations of two low data rate links, one low datarate with one high data rate link, or two high data rate links. A highdata rate UWB link can also be used to connect the user device 2006wirelessly to other equipment over an UWB link that requires a high datathroughput link, such as an external video camera with UWB hardware.

For systems requiring short time periods of high data rate traffic, thelow data rate UWB link can be used to signal the requirement for a highdata rate UWB link. The high data rate UWB link would be placed in ahibernation mode until receiving a command to be activated by a messagesent across the low data rate UWB link from the user device to the otherunits going to receive the high data rate UWB communications message.This approach requires the nodes using the high data rate UWB link tohave two UWB hardware elements, which increases size, but can offersignificant power consumption reduction, by using the UWB hardwarehibernation mode on the high data rate UWB link units.

The UWB link processor 2012 connects the internal video camera 2014 tothe UWB hardware 2010 that supports the high data rate UWB link toanother user device 2017 and/or an access point 2026. A multicasttransmission can be used to send the high data rate information, such asvideo, to the user device 2016 and access point 2026 in the sametransmission to increase data throughput capability. This method can beused to transmit video and/or picture information to other medical stafffor supportive help at the point of care, storage of patientinformation, and support of preparation for the patient arrival at thenext medical site. Besides medical applications, this dual UWB link canbe used to support multiple links between low data and high data ratesensors, such as for military or commercial applications.

This dual UWB link approach can also be used to provide a relay elementthat can be cascaded for extended communications range. To optimize therelay element performance, operation at two different channelfrequencies combined with external directional antennas would reduce theinterference between the two UWB links. Spectral reuse of channelfrequencies would be done based on the communications coverage area andlocation of the different relay elements within the coverage area tomitigate interference. Channel interference measurement approachespresently described can be used to adjust the channel frequencies acrossthe network to mitigate interference and increase data throughput acrossthe UWB network.

The system 2100 is one of numerous modifications to system 2000 that cansupport low and/or high data rate communication links. System 2100 caninclude one or more patient care devices 2102 that are connected on thelow data rate UWB link to the user device 2106. The UWB hardware 2104 inthe patient care device 2102 communications to the UWB hardware 2108 inthe user device 2106 over the lower data rate UWB communications linksetup by the UWB link processor 2112 in the user device 2106. The userdevice 2106 contains two UWB hardware elements that can be configured toprovide a low or high data rate UWB link. For the specific systemconfiguration 2100 given in FIG. 21, the user device UWB hardware 2108provides connection to the low data rate UWB link and the user deviceUWB hardware 2110 provides connection to the high data rate UWB link forsupporting video and other higher data rate applications. The low datarate link provided by the UWB hardware 2108 enables the user device 2106to support low data rate information to another user device 2116 or/andan access point 2126 connected to a radio 2132 capable of supporting thelow data rate information for extended communications range. For lowdata rate information in the access point 2126, the UWB hardware 2128 isconfigured to operate over the low data rate link. The high data ratelink provided by the UWB hardware 2110 enables the user device 2106 tosupport video traffic to another user device 2116 or/and an access point2126 connected to a radio 2132 capable of supporting the high data rateinformation for extended communications range. For high data rateinformation in the access point 2126, the UWB hardware 2128 isconfigured to operate over the high data rate link. Interface betweenthe UWB hardware 2128 and the radio 2132 used for extended rangecommunications of either low or high data rate transmission is supportby the interface element 2130. This single radio 2130 configurationconnected to the access point 2126 requires a radio capable ofsupporting high data rate communications. For this configuration, thelow and high data rate information at the access point would becompeting for the same radio channel, unless two different radio systemswere supplied. An algorithm in the access point would control access tothe radio link based on a priority level of the information that needsto be sent. The single UWB hardware 2128 in the access point 2126 can beconfigured to support a low data rate and high data rate radio as shownin FIG. 21. For this configuration, the UWB hardware 2128 output isrouted to the low data rate radio for low data rate transmissions andthe high data rate radio for high data rate transmissions. This radioconfiguration prevents the low and high data rate information fromcompeting for the same radio channel, allowing both transmissions duringthe same time periods assuming that each radio channel operates on adifferent carrier frequency to prevent channel interference.

FIG. 22 is a process flow showing a method 2200 having one or morefeatures consistent with the presently described subject matteraddressing the two UWB data rate configuration, which typically would beconfigured in a low and/or high data rate UWB links.

This same approach of switching between low and high data ratetransmission using a single UWB hardware element can be easily appliedto the use devices. The operations of method 2200 can be performed byone or more of the features described herein.

At 2202, an initial low or high data rate UWB link exists that providescommunications to the different nodes within the UWB network. Since theuser device for a medical application will typically be connected topatient care devices that are collecting patient data for transmissionto the user device, this initial link will typically be a low data rateUWB link. This does not exclude an initial high data rate UWB linkwithin the UWB network.

At 2204, the user device uses the existing UWB link to send the channeloperational information for the support of high data rate traffic to theappropriate user device(s) and access point. The access point 2028 shownin FIG. 20 consists of two UWB hardware elements and the access pointshown in FIG. 21 consists of one UWB hardware element. Using a singleUWB hardware element requires the access point to switch between the lowand high data rate UWB link, where the low data rate UWB link providesthe channel information to the access point for the high data rate UWBlink. By operating on the low data rate UWB link, the channelinformation for the high data rate link is available at the accesspoint, providing a fast synchronization with the high data rate UWBlink.

A dual UWB hardware approach, like shown in FIG. 20 for the access pointenables the low data rate UWB link operation to collect channelinformation that can be used to select the channel with lessinterference and highest data rate capacity for the high data rate UWBlink.

Another approach to the access point network connection allows the UWBhardware to operate in the UWB channel search mode and synchronize withthe newly established low or high date rate UWB link. This approachrequires less hardware, but will require more time to establish the linkto the access point, since the access point does not know theoperational channel for the UWB link and must search the UWB channels tolocate the channel being used for the UWB link.

At 2206, the high data rate UWB link is established between thedifferent node elements consisting of user devices and access point asshown in FIG. 20, which does not exclude other types of devices with UWBhardware to be connected to the high data rate UWB link network.

At 2208, the high data information is sent across the UWB link betweenthe different node elements consisting of user devices and access pointas shown in FIG. 20, which does not exclude other types of devices withUWB hardware to be connected to the high data rate UWB link network.

At 2210, channel information is being collected during the transmit andreceived operations over the UWB link to determine interference and datarate capacity of the existing operational channel using the previousdisclosed approaches. The channel information is processed to determineif a channel change should be made.

At 2212, the high data rate UWB link performs a channel change based onthe measured channel performance information and continues transmissionof high data rate information when the network is reestablished.

One or more of the features described herein can be performed by one ormore processors. The processor(s) can be configured to provideinformation processing capabilities to one or more computing deviceshaving one or more features consistent with the current subject matter.The computing device(s) can be, for example, a smart device, atelephone, a computer, or the like. Processor(s) may include one or moreof a digital processor, an analog processor, a digital circuit designedto process information, an analog circuit designed to processinformation, a state machine, and/or other mechanisms for electronicallyprocessing information. Processors can be a single entity, multipleentities, collocated, or located in separate buildings. In someimplementations, the processor(s) can include a plurality of processingunits. These processing units can be physically located within the samedevice, or processor and may represent processing functionality of aplurality of devices operating in coordination. The processor can beconfigured to execute machine-readable instructions, which, whenexecuted by the processor(s) may cause the processor(s) to perform oneor more of the functions described in the present description. Thefunctions described herein may be executed by software; hardware;firmware; some combination of software, hardware, and/or firmware;and/or other mechanisms for configuring processing capabilities on theprocessor(s).

The processor(s) can be disposed in one or more of the PCD, medic's UD,a server, or the like, and the one or more of the processors can beconfigured to perform the various features described herein. Theprocessor(s) can be configured to execute machine-readable instructionsstored on electronic storage media. The machine-readable instructions,when executed by the processor(s), can cause the processor(s) to performone or more of the functions described herein. In some variations, oneprocessor disposed at one device may perform a first set of functionsand a different processor disposed at a different device may perform asecond set of functions, for example, a processor(s) at a UD may performthe bulk of selecting and/or determining the burst data rate fortransmission between a PCD and a UD.

One or more aspects or features of the subject matter described hereincan be realized in digital electronic circuitry, integrated circuitry,specially designed application specific integrated circuits (ASICs),field programmable gate arrays (FPGAs) computer hardware, firmware,software, and/or combinations thereof. These various aspects or featurescan include implementation in one or more computer programs that areexecutable and/or interpretable on a programmable system including atleast one programmable processor, which can be special or generalpurpose, coupled to receive data and instructions from, and to transmitdata and instructions to, a storage system, at least one input device,and at least one output device. The programmable system or computingsystem may include clients and servers. A client and server aregenerally remote from each other and typically interact through acommunication network. The relationship of client and server arises byvirtue of computer programs running on the respective computers andhaving a client-server relationship to each other.

These computer programs, which can also be referred to programs,software, software applications, applications, components, or code,include machine instructions for a programmable processor, and can beimplemented in a high-level procedural language, an object-orientedprogramming language, a functional programming language, a logicalprogramming language, and/or in assembly/machine language. As usedherein, the term “machine-readable medium” refers to any computerprogram product, apparatus and/or device, such as for example magneticdiscs, optical disks, memory, and Programmable Logic Devices (PLDs),used to provide machine instructions and/or data to a programmableprocessor, including a machine-readable medium that receives machineinstructions as a machine-readable signal. The term “machine-readablesignal” refers to any signal used to provide machine instructions and/ordata to a programmable processor. The machine-readable medium can storesuch machine instructions non-transitorily, such as for example as woulda non-transient solid-state memory or a magnetic hard drive or anyequivalent storage medium. The machine-readable medium can alternativelyor additionally store such machine instructions in a transient manner,such as for example as would a processor cache or other random accessmemory associated with one or more physical processor cores.

To provide for interaction with a user, one or more aspects or featuresof the subject matter described herein can be implemented on a computerhaving a display device, such as for example a cathode ray tube (CRT) ora liquid crystal display (LCD) or a light emitting diode (LED) monitorfor displaying information to the user and a keyboard and a pointingdevice, such as for example a mouse or a trackball, by which the usermay provide input to the computer. Other kinds of devices can be used toprovide for interaction with a user as well. For example, feedbackprovided to the user can be any form of sensory feedback, such as forexample visual feedback, auditory feedback, or tactile feedback; andinput from the user may be received in any form, including, but notlimited to, acoustic, speech, or tactile input. Other possible inputdevices include, but are not limited to, touch screens or othertouch-sensitive devices such as single or multi-point resistive orcapacitive trackpads, voice recognition hardware and software, opticalscanners, optical pointers, digital image capture devices and associatedinterpretation software, and the like.

In the descriptions above and in the claims, phrases such as “at leastone of” or “one or more of” may occur followed by a conjunctive list ofelements or features. The term “and/or” may also occur in a list of twoor more elements or features. Unless otherwise implicitly or explicitlycontradicted by the context in which it used, such a phrase is intendedto mean any of the listed elements or features individually or any ofthe recited elements or features in combination with any of the otherrecited elements or features. For example, the phrases “at least one ofA and B;” “one or more of A and B;” and “A and/or B” are each intendedto mean “A alone, B alone, or A and B together.” A similarinterpretation is also intended for lists including three or more items.For example, the phrases “at least one of A, B, and C;” “one or more ofA, B, and C;” and “A, B, and/or C” are each intended to mean “A alone, Balone, C alone, A and B together, A and C together, B and C together, orA and B and C together.” Use of the term “based on,” above and in theclaims is intended to mean, “based at least in part on,” such that anunrecited feature or element is also permissible.

The subject matter described herein can be embodied in systems,apparatus, methods, and/or articles depending on the desiredconfiguration. The implementations set forth in the foregoingdescription do not represent all implementations consistent with thesubject matter described herein. Instead, they are merely some examplesconsistent with aspects related to the described subject matter.Although a few variations have been described in detail above, othermodifications or additions are possible. In particular, further featuresand/or variations can be provided in addition to those set forth herein.For example, the implementations described above can be directed tovarious combinations and subcombinations of the disclosed featuresand/or combinations and subcombinations of several further featuresdisclosed above. In addition, the logic flows depicted in theaccompanying figures and/or described herein do not necessarily requirethe particular order shown, or sequential order, to achieve desirableresults. Other implementations may be within the scope of the followingclaims.

What is claimed is:
 1. A system comprising: at least one processor; amemory storing machine-readable instructions which, when executed by theat least one processor, cause the at least one processor to perform oneor more operations, the one or more operations comprising: receiving, ata first set of slave nodes, a wideband signal, the first set of slavenodes comprising one or more slave nodes and being at least a first partof a wideband network, the wideband network using a wideband channel;measuring, at the first set of slave nodes, a signal strength of thewideband signal; determining, at the first set of slave nodes, a noiselevel for the wideband signal; estimating, at the first set of slavenodes, a first estimated amount of interference of the wideband signal;transmitting, from the first set of slave nodes and to a master node,the first estimated amount of interference; and generating, at themaster node, an estimated amount of network interference by comparingthe first estimated amount of interference with a second estimatedamount of interference from a second set of slave nodes, the second setof slave nodes being at least a second part of the wideband network. 2.The system of claim 1, wherein the one or more operations furthercomprise: selecting, at the master node and in response to the estimatedamount of network interference exceeding a threshold interference value,another wideband channel for the wideband network; and transmitting,from the master node and to the first set of slave nodes and the secondset of slave nodes, an instruction to move to the another widebandchannel.
 3. The system of claim 2, wherein the one or more operationsfurther comprise: receiving, at the master node and from the first setof slave nodes, an acknowledgement from the first set of slave nodes ofthe instruction; and moving, in response to the receiving of theacknowledgement, from the wideband channel to the another widebandchannel.
 4. The system of claim 1, wherein the determining of the noiselevel is based on a number of symbol corrections required for thewideband signal.
 5. The system of claim 1, wherein the one or moreoperations further comprise: estimating, at the master node and based ona master node signal strength of a master node wideband signal receivedat the master node and based on a master node noise level for the masternode wideband signal, a master node estimated amount of interference ofthe master node wideband signal; and wherein the estimated amount ofnetwork interference is further based on the master node estimatedamount of interference of the master node wideband signal.
 6. The systemof claim 1, wherein the first set of slave nodes comprise a patient caredevice and the master node comprises a user device.
 7. The system ofclaim 1, wherein the wideband signal received at the first set of slavenodes comprises a signal burst preamble.
 8. A method comprising:receiving, at a first set of slave nodes, a wideband signal, the firstset of slave nodes comprising one or more slave nodes and being at leasta first part of a wideband network, the wideband network using awideband channel; measuring, at the first set of slave nodes, a signalstrength of the wideband signal; determining, at the first set of slavenodes, a noise level for the wideband signal; estimating, at the firstset of slave nodes, a first estimated amount of interference of thewideband signal; transmitting, from the first set of slave nodes and toa master node, the first estimated amount of interference; andgenerating, at the master node, an estimated amount of networkinterference by comparing the first estimated amount of interferencewith a second estimated amount of interference from a second set ofslave nodes, the second set of slave nodes being at least a second partof the wideband network.
 9. The method of claim 8, further comprising:selecting, at the master node and in response to the estimated amount ofnetwork interference exceeding a threshold interference value, anotherwideband channel for the wideband network; and transmitting, from themaster node and to the first set of slave nodes and the second set ofslave nodes, an instruction to move to the another wideband channel. 10.The method of claim 9, further comprising: receiving, at the master nodeand from the first set of slave nodes, an acknowledgement from the firstset of slave nodes of the instruction; and moving, in response to thereceiving of the acknowledgement, from the wideband channel to theanother wideband channel.
 11. The method of claim 8, wherein thedetermining of the noise level is based on a number of symbolcorrections required for the wideband signal.
 12. The method of claim 8,further comprising: estimating, at the master node and based on a masternode signal strength of a master node wideband signal received at themaster node and based on a master node noise level for the master nodewideband signal, a master node estimated amount of interference of themaster node wideband signal; and wherein the estimated amount of networkinterference is further based on the master node estimated amount ofinterference of the master node wideband signal.
 13. The method of claim8, wherein the first set of slave nodes comprise a patient care deviceand the master node comprises a user device.
 14. The method of claim 8,wherein the wideband signal received at the first set of slave nodescomprises a signal burst preamble.